General: TN3151 Choosing the right networking API Networking Overview document — Despite the fact that this is in the archive, this is still really useful. TLS for App Developers DevForums post Choosing a Network Debugging Tool documentation WWDC 2019 Session 712 Advances in Networking, Part 1 — This explains the concept of constrained networking, which is Apple’s preferred solution to questions like How do I check whether I’m on Wi-Fi? TN3135 Low-level networking on watchOS Adapt to changing network conditions tech talk Foundation networking: DevForums tags: Foundation, CFNetwork URL Loading System documentation — NSURLSession, or URLSession in Swift, is the recommended API for HTTP[S] on Apple platforms. Network framework: DevForums tag: Network Network framework documentation — Network framework is the recommended API for TCP, UDP, and QUIC on Apple platforms. Network Extension (including Wi-Fi on iOS): See Network Extension Resources Wi-Fi Fundamentals Wi-Fi on macOS: DevForums tag: Core WLAN Core WLAN framework documentation Wi-Fi Fundamentals Secure networking: DevForums tags: Security Apple Platform Security support document Preventing Insecure Network Connections documentation — This is all about App Transport Security (ATS). Available trusted root certificates for Apple operating systems support article Requirements for trusted certificates in iOS 13 and macOS 10.15 support article About upcoming limits on trusted certificates support article Apple’s Certificate Transparency policy support article Technote 2232 HTTPS Server Trust Evaluation Technote 2326 Creating Certificates for TLS Testing QA1948 HTTPS and Test Servers Miscellaneous: More network-related DevForums tags: 5G, QUIC, Bonjour On FTP DevForums post Using the Multicast Networking Additional Capability DevForums post Investigating Network Latency Problems DevForums post Local Network Privacy FAQ DevForums post Extra-ordinary Networking DevForums post Share and Enjoy — Quinn “The Eskimo!” @ Developer Technical Support @ Apple let myEmail = "eskimo" + "1" + "@" + "apple.com"

We have a development where we are MDM managing iOS devices and attempting to enforce mutual TLS for all interactions with the MDM. We are DEP provisionng an enrolment profile that utilises an ACME hardware attested Device Identity Certificate. All interactions with the MDM endpoints are correctly utilising the ACME certificate for the client mutual TLS handshake. The certificate has Client Authentication Extended Key Usage. Behind the same API gateway and on the same SNI we are also serving paths to Enterprise application manifests and IPAs. We can see from the phone log and from packet traces the iOS device doesn't offer the Device Identity Certificate for client authentication when retrieving these URLs. We have also tried adding non ACME client certificates from the root trusted by the server to the initial profile with exactly the same outcome. If we temporarily disable the mutualTLS we can see that the request for the manifest has a userAgent of "com.apple.appstored/1.0 iOS/18.2 model/iPhone17,3 hwp/t8140 build/22C5125e (6; dt:329) AMS/1" which is not the same as the mdm interactions. Is it actually possible to achieve mutualTLS to authenticate these downloads or is a different solution required ? Any advice greatly appreciated.

hello, we're currently working on a way to adapt the behavior of our app when the device is running with a low free memory remaining, or a bad network. For the network, we though about implementing a speedtest, but the issue with this solution is that we want to test regularly the quality of the network, so if the device is running with a poor/bad network, the speedtest with stuck the app. I was looking for other way to check the displayed informations in the status bar: private func getWiFiRSSI() -> Int? { let app = UIApplication.shared var rssi: Int? let exception = tryBlock { guard let statusBar = app.value(forKey: "statusBar") as? UIView else { return } if let statusBarMorden = NSClassFromString("UIStatusBar_Modern"), statusBar .isKind(of: statusBarMorden) { return } guard let foregroundView = statusBar.value(forKey: "foregroundView") as? UIView else { return } for view in foregroundView.subviews { if let statusBarDataNetworkItemView = NSClassFromString("UIStatusBarDataNetworkItemView"), view .isKind(of: statusBarDataNetworkItemView) { if let val = view.value(forKey: "wifiStrengthRaw") as? Int { rssi = val break } } } } if let exception = exception { print("getWiFiRSSI exception: \(exception)") } return rssi } I've checked the AppStore Guidelines but I'm not sure that this kind of code will not be subject to rejection by the Review team. Anyone having trying to submit with a similar approach? Did you already managed to monitor network regularly, without using a speedtest? Thanks for the help!

Hi, all. We have a camera with only one WiFi module. It supports AP and STA modes coexisting, but the WiFi of AP and STA can only be in the same channel at the same time, that is, 2.4G or 5G. In the initial state, the App is connected to the camera through 5G WiFi, and the camera is in AP mode. When entering the network configuration mode, the camera will start the STA mode, and the AP and STA modes coexist. When the user selects 2.4G WiFi, the AP mode will switch from 5G to 2.4G. Android's WiFi and socket are not disconnected, iOS's socket will be disconnected 100%, and WiFi may be disconnected. What is the reason for this? Is there any way to solve it?

We have Mac OS VM which has two network interfaces and both are active. In our application we need “State:/Network/Global/IPv6” to do some task but on this machine it seems to be missing, however if we disable one of the interface then the same setting seems to be available and our code works fine. Please find the attached screenshots of working & non-working details:

I am running Xcode 16.1, macOS 15.1 , iOS 18.1, and I see the error when trying to run the Instruments Network Profile

MINI M2 Apache httpd stopped serving with this in log: "bug_type":"312","os_version":"macOS 15.2 (24C5079e)"} {"issueCategory":"hitch","logType":"Tailspin","uploadAttemptCount":0, Sequoia 15.2 Beta Server runs about 2 hours and then need to reboot computer to restart to server remote viewers. Brew Service ReStart and sudo apachectl graceful restart server for localhost but they will not restart server for remote viewers.

I am experiencing an issue while recording audio using AVAudioEngine with the installTap method. I convert the AVAudioPCMBuffer to Data and send it to a UDP server. However, when I receive the Data and play it back, there is continuous crackling noise during playback. I am sending audio data using this library "https://github.com/mindAndroid/swift-rtp" by creating packet and send it. Please help me resolve this issue. I have attached the code reference that I am currently using. Thank you. ViewController.swift

Our product (rockhawk.ca) uses the Multipeer Connectivity framework for peer-to-peer communication between multiple iOS/iPadOS devices. My understanding is that MC framework communicates via three methods: 1) infrastructure wifi (i.e. multiple iOS/iPadOS devices are connected to the same wifi network), 2) peer-to-peer wifi, or 3) Bluetooth. In my experience, I don't believe I've seen MC use Bluetooth. With wifi turned off on the devices, and Bluetooth turned on, no connection is established. With wifi on and Bluetooth off, MC works and I presume either infrastructure wifi (if available) or peer-to-peer wifi are used. I'm trying to overcome two issues: Over time (since iOS 9.x), the radio transmit strength for MC over peer-to-peer wifi has decreased to the point that range is unacceptable for our use case. We need at least 150 feet range. We would like to extend this support to watchOS and the MC framework is not available. Regarding #1, I'd like to confirm that if infrastructure wifi is available, MC uses it. If infrastructure wifi is not available, MC uses peer-to-peer wifi. If this is true, then we can assure our customers that if infrastructure wifi is available at the venue, then with all devices connected to it, range will be adequate. If infrastructure wifi is not available at the venue, perhaps a mobile wifi router (battery operated) could be set up, devices connected to it, then range would be adequate. We are about to test this. Reasonable? Can we be assured that if infrastructure wifi is available, MC uses it? Regarding #2, given we are targeting minimum watchOS 7.0, would the available networking APIs and frameworks be adequate to implement our own equivalent of the MC framework so our app on iOS/iPadOS and watchOS devices could communicate? How much work? Where would I start? I'm new to implementing networking but experienced in using the MC framework. I'm assuming that I would write the networking code to use infrastructure wifi to achieve acceptable range. Many thanks! Tim

Hi, I have a SAML authentication scenario with MFA(probably Okta) in my app that runs in WKWebView using Cordova. I am currently doing POC to authenticate PIV certificates(either one of the 3 Issuers: DISA Purebred, Intercede and Entrust) in WKWebView with Cordova. As if now, I have found that WKNavigationDelegate method: didReceive challenge, we can authenticate the certificate. Also, these PIV certificates which are stored in the form of .p12 in Apple's keychain group needs to be imported using function: SecPKCS12Import. Please let me know if my understanding is correct or if there are any implementation challenges in WKWebView with Cordova. I would highly appreciate if any information regarding this can be provided.

Hello, I was able to use the TicTackToe code base and modify it such that I have a toggle at the top of the screen that allows me to start / stop the NWBrowser and NWListener. I have it setup so when the browser finds another device it attempts to connect to it. I support N devices / connections. I am able to use the NWParameters extension that is in the TickTackToe game that uses a passcode and TLS. I am able to send messages between devices just fine. Here is what I used extension NWParameters { // Create parameters for use in PeerConnection and PeerListener. convenience init(passcode: String) { // Customize TCP options to enable keepalives. let tcpOptions = NWProtocolTCP.Options() tcpOptions.enableKeepalive = true tcpOptions.keepaliveIdle = 2 // Create parameters with custom TLS and TCP options. self.init(tls: NWParameters.tlsOptions(passcode: passcode), tcp: tcpOptions) // Enable using a peer-to-peer link. self.includePeerToPeer = true } // Create TLS options using a passcode to derive a preshared key. private static func tlsOptions(passcode: String) -> NWProtocolTLS.Options { let tlsOptions = NWProtocolTLS.Options() let authenticationKey = SymmetricKey(data: passcode.data(using: .utf8)!) let authenticationCode = HMAC<SHA256>.authenticationCode(for: "HI".data(using: .utf8)!, using: authenticationKey) let authenticationDispatchData = authenticationCode.withUnsafeBytes { DispatchData(bytes: $0) } sec_protocol_options_add_pre_shared_key(tlsOptions.securityProtocolOptions, authenticationDispatchData as __DispatchData, stringToDispatchData("HI")! as __DispatchData) sec_protocol_options_append_tls_ciphersuite(tlsOptions.securityProtocolOptions, tls_ciphersuite_t(rawValue: TLS_PSK_WITH_AES_128_GCM_SHA256)!) return tlsOptions } // Create a utility function to encode strings as preshared key data. private static func stringToDispatchData(_ string: String) -> DispatchData? { guard let stringData = string.data(using: .utf8) else { return nil } let dispatchData = stringData.withUnsafeBytes { DispatchData(bytes: $0) } return dispatchData } } When I try to modify it to use QUIC and TLS 1.3 like so extension NWParameters { // Create parameters for use in PeerConnection and PeerListener. convenience init(psk: String) { self.init(quic: NWParameters.quicOptions(psk: psk)) self.includePeerToPeer = true } private static func quicOptions(psk: String) -> NWProtocolQUIC.Options { let quicOptions = NWProtocolQUIC.Options(alpn: ["h3"]) let authenticationKey = SymmetricKey(data: psk.data(using: .utf8)!) let authenticationCode = HMAC<SHA256>.authenticationCode(for: "hello".data(using: .utf8)!, using: authenticationKey) let authenticationDispatchData = authenticationCode.withUnsafeBytes { DispatchData(bytes: $0) } sec_protocol_options_set_min_tls_protocol_version(quicOptions.securityProtocolOptions, .TLSv13) sec_protocol_options_set_max_tls_protocol_version(quicOptions.securityProtocolOptions, .TLSv13) sec_protocol_options_add_pre_shared_key(quicOptions.securityProtocolOptions, authenticationDispatchData as __DispatchData, stringToDispatchData("hello")! as __DispatchData) sec_protocol_options_append_tls_ciphersuite(quicOptions.securityProtocolOptions, tls_ciphersuite_t(rawValue: TLS_AES_128_GCM_SHA256)!) sec_protocol_options_set_verify_block(quicOptions.securityProtocolOptions, { _, _, sec_protocol_verify_complete in sec_protocol_verify_complete(true) }, .main) return quicOptions } // Create a utility function to encode strings as preshared key data. private static func stringToDispatchData(_ string: String) -> DispatchData? { guard let stringData = string.data(using: .utf8) else { return nil } let dispatchData = stringData.withUnsafeBytes { DispatchData(bytes: $0) } return dispatchData } } I get the following errors in the console boringssl_session_handshake_incomplete(241) [C3:1][0x109d0c600] SSL library error boringssl_session_handshake_error_print(44) [C3:1][0x109d0c600] Error: 4459057536:error:100000ae:SSL routines:OPENSSL_internal:NO_CERTIFICATE_SET:/Library/Caches/com.apple.xbs/Sources/boringssl/ssl/tls13_server.cc:882: boringssl_session_handshake_incomplete(241) [C4:1][0x109d0d200] SSL library error boringssl_session_handshake_error_print(44) [C4:1][0x109d0d200] Error: 4459057536:error:100000ae:SSL routines:OPENSSL_internal:NO_CERTIFICATE_SET:/Library/Caches/com.apple.xbs/Sources/boringssl/ssl/tls13_server.cc:882: nw_endpoint_flow_failed_with_error [C3 fe80::1884:2662:90ca:b011%en0.65328 in_progress channel-flow (satisfied (Path is satisfied), viable, interface: en0[802.11], scoped, ipv4, dns, uses wifi)] already failing, returning nw_endpoint_flow_failed_with_error [C4 192.168.0.98:65396 in_progress channel-flow (satisfied (Path is satisfied), viable, interface: en0[802.11], scoped, ipv4, dns, uses wifi)] already failing, returning quic_crypto_connection_state_handler [C1:1] [2ae0263d7dc186c7-] TLS error -9858 (state failed) nw_connection_copy_connected_local_endpoint_block_invoke [C3] Client called nw_connection_copy_connected_local_endpoint on unconnected nw_connection nw_connection_copy_connected_remote_endpoint_block_invoke [C3] Client called nw_connection_copy_connected_remote_endpoint on unconnected nw_connection nw_connection_copy_protocol_metadata_internal_block_invoke [C3] Client called nw_connection_copy_protocol_metadata_internal on unconnected nw_connection quic_crypto_connection_state_handler [C2:1] [84fdc1e910f59f0a-] TLS error -9858 (state failed) nw_connection_copy_connected_local_endpoint_block_invoke [C4] Client called nw_connection_copy_connected_local_endpoint on unconnected nw_connection nw_connection_copy_connected_remote_endpoint_block_invoke [C4] Client called nw_connection_copy_connected_remote_endpoint on unconnected nw_connection nw_connection_copy_protocol_metadata_internal_block_invoke [C4] Client called nw_connection_copy_protocol_metadata_internal on unconnected nw_connection Am I missing some configuration? I noticed with the working code that uses TCP and TLS that there is an NWParameters initializer that accepts tls options and tcp option but there isnt one that accepts tls and quic. Thank you for any help :)

On iOS beta, monitoring network usage using the getifaddrs API sporadically causes system volume spikes. This happens even though the application does not interact with any audio-related code. The issue persists across different polling intervals (e.g., 0.05s to 1s) and only occurs when invoking getifaddrs. Replacing the API calls with mock data eliminates the problem, suggesting a potential issue with getifaddrs in the beta environment. The application updates UI elements based on network activity, but the volume spikes occur independently of UI or other observable app behavior. Steps to Reproduce: Create an app that monitors network usage using the getifaddrs API. Fetch network statistics on a timer (e.g., every 0.05 seconds). Observe system behavior while running the app on iOS beta. Note sporadic volume spikes during app runtime. Expected Result: Polling network usage with getifaddrs should not affect system volume or other unrelated resources. Actual Result: System volume spikes occasionally when network statistics are retrieved using getifaddrs. iOS 18.2 Beta, Tested on physical device ( iPhone 15 Pro )

I am getting recurring errors running code on macOS 15.1 on arm that is using a volume mounted from a machine running macOS 14.7.1 on x86. The code I am running copies files to the remote volume and deletes files and directories on the remote volume. The files and directories it deletes are typically files it previously had copied. The problem is that I get permission failures trying to delete certain directories. After this happens, if I try to list the directory using Terminal on the 15.1 system, I get a strange error: ls -lA TestVAppearances.app/Contents/runtime-arm/Contents total 0 ls: fts_read: Permission denied If I try to list the directory on the target (14.7.1) system, there is no error: TestVAppearances.app/Contents/runtime-arm/Contents: total 0

I am planning to implement Peer to Peer data exchange between 2 iOS devices. I have the following queries. My devices are connected through Ethernet. I would prefer to use this route if possible before switching over to Wifi. I can see there is an option to use prohibitedInterfaceTypes but that doesn't guarantee the route to use Ethernet when there are multiple available. Does the connection automatically switch between ethernet and Wifi or does that have to be handled via isViable and betterPathAvailable? I'm unsure when I should be using a custom framing protocol. I just need to exchange codable objects between the devices. Is the custom protocol required only if I use TCP as the underlying protocol? Can NSURLSessionStreamTask be used for this use case?

Hi, I'm using the Network framework to browse for devices on the local network. Unfortunately, I get many crash reports that crash in nw_browser_cancel, of which two are attached. This discussion seems to have a similar issue, but it was never resolved: https://forums.developer.apple.com/forums/thread/696037 Contrary to the situation in the linked thread, my implementation uses DispatchQueue.main as the queue for the browser, so I don't think over-releasing the queue is the problem. I am unable to reproduce this problem myself, but one of my users can reproduce it reliably it seems. How can I resolve this crash? 2024-11-10_14-24-35.3886_+0100-4fdbdb8e944a4b655d60df53da3aa8c759f4fd1f.crash 2024-11-08_08-54-31.6366_+0100-303cabefb74bf89cdea3127b1cad122ee46016f2.crash

Kindly suggest the best approach for the below requirement. Requirement Summary: I have a camera that generates its own Wi-Fi network with some specifications, and I need my iOS app to automatically connect to that Wi-Fi whenever it's in range. This Wi-Fi network is used for transferring files between the camera and the iOS app and to give commands to camera to do certain actions. This Wi-Fi does not provide internet access. Details: The iOS app should automatically connect to the camera's Wi-Fi network once it launches. The camera's Wi-Fi does not have internet access; it is purely for file transfers (e.g., photos/videos) between the camera and the iOS app and to command camera to do certain actions The iOS device should still use mobile data for internet access while connected to the camera's Wi-Fi. The mobile data will be used to upload files to the cloud, as I have a large data plan available for internet use. The app should maintain the connection to the camera's Wi-Fi as long as the iOS device is within proximity of the camera. If the device moves out of range and then comes back, the iOS app should prefer and reconnect to the camera's Wi-Fi over any other available networks. I am looking for a solution or approach that can make this seamless, ensuring a stable connection between the camera and the iOS app while prioritizing mobile data for internet connectivity.

Hello, I have a company laptop thats connected to the internet without a VPN. I need to be able to resolve my company's sub domains using a specific dns server, and have all other domains resolved by the system wide name server. In windows, this is trivial to do. In an admin powershell I run "Add-DnsClientNrptRule -Namespace ".foo.mycompany.com" -Nameserver "127.0.0.1" and resolution requests for *.foo.mycompany.com is sent to a name server running on the localhost. All other dns resolution requests are handled by the system configured resolver. MacOS does have the /etc/resolver/ solution for this, but my understanding from these forums is that this is not the recommended approach. Note - I have tried it and it works. AFAIU, the recommended approach is to create a system Network extension using NEDNSProxyProvider, override handleNewFlow() and do what's necessary. The issue with this solution is that it requires handling all the dns flow parsing of DNS datagrams to extract the host forwarding the datagrams to the appropriate dns server Handle responses. Deal with flow control Handle edge cases. I was hoping for something much simpler than us needing to implement datagram parsing. Could you please shed light on our options and how we could proceed ?

In the past, I used to ping my iPhone‘s local IP address via UDP. If local network permissions were not enabled, it would return an error. If they were enabled, it would return success, which I used to determine whether my app had local network permissions enabled. Now, with iOS 18, it seems to not work anymore. Regardless of whether local network permissions are enabled, pinging the iPhone‘s local IP address always returns success. Is there any other good method to check this permission status? Case-ID: 9934335

Hello! I'd like to ask about the best way of getting a list of DNS servers from the system (iOS & macOS). Why? I am using NEPacketTunnelProvider to implement a VPN app. When a device joins a network with a Captive Portal and the VPN is on, the VPN should redirect DNS queries to the DNS servers that were received from the network's DHCP server. So that my VPN is able to correctly reroute the traffic which is not blocked by the network's gateway and the Captive Portal landing page is served. When I don't do anything, the traffic goes to the tunnel and the tunnel's encrypted traffic is then dropped by the gateway serving the Captive Portal. When I temporarily turn off the VPN, opt out of all the traffic or pass the traffic to the system resolver, the traffic gets affected by other network settings (like DNSSettings) which leads to the same situation - the user not being able to authenticate with the Captive Portal. So far, I have tried multiple ways, including res_9_getservers but unsuccessfully. As a part of my investigation, I have found out that the /etc/resolv.conf file is not populated with DNS servers until the Captive Portal is acknowledged by the user which makes getaddrinfo unusable to achieve my goal. But I am not sure if that's a bug or intended behavior. Thank you for your help!

Dear Apple Support Team, I hope this message finds you well. I am writing to report an issue I have encountered with Wi-Fi connectivity on my iPhone 16 series running iOS 18.0. The problem occurs as follows: When attempting to connect my iPhone 16 series (iOS 18.0) to a Wi-Fi network, the connection always fails. After this failed attempt, any other iPhone (not from the 16 series) running iOS 18.0 also fails to connect to the same Wi-Fi network. However, if I restart the Wi-Fi router, the non-iPhone 16 series devices can successfully connect to the Wi-Fi network. To further investigate, I used Wireshark to monitor the network traffic. I observed that the iPhone sends a DHCP Discover message, but the Wi-Fi router does not respond with a DHCP Offer message. Based on these observations, it appears that the issue is triggered by the iPhone 16 series running iOS 18.0, which causes the Wi-Fi router to malfunction and prevents other devices from connecting. Additionally, I have tried all the steps listed on the following site, but the issue persists: https://support.apple.com/en-us/111786 Could you please investigate this issue and provide guidance on how to resolve it? If this is a known bug, is there a planned update to address it? Thank you for your assistance. I look forward to your prompt response. Best regards, WJohn

Hi, I would like to know if it is safe to call the uploadTask from URLSession from the main thread ? We've a user who is reporting repeated crashes at startup, here is the stack we see: Exception Type: EXC_CRASH (SIGKILL) Exception Codes: 0x0000000000000000, 0x0000000000000000 Termination Reason: FRONTBOARD 2343432205 <RBSTerminateContext| domain:10 code:0x8BADF00D explanation:scene-update watchdog transgression: app<com.appspot.myApp(E7590BB1-722C-491D-9199-F867DE4B880A)>:2212 exhausted real (wall clock) time allowance of 10.00 seconds ProcessVisibility: Background ProcessState: Running WatchdogEvent: scene-update WatchdogVisibility: Background WatchdogCPUStatistics: ( "Elapsed total CPU time (seconds): 21.260 (user 10.230, system 11.030), 35% CPU", "Elapsed application CPU time (seconds): 0.006, 0% CPU" ) reportType:CrashLog maxTerminationResistance:Interactive> Triggered by Thread: 0 Thread 0 name: Dispatch queue: com.apple.main-thread Thread 0 Crashed: 0 libsystem_kernel.dylib 0x1def7a688 mach_msg2_trap + 8 1 libsystem_kernel.dylib 0x1def7dd98 mach_msg2_internal + 80 2 libsystem_kernel.dylib 0x1def7dcb0 mach_msg_overwrite + 424 3 libsystem_kernel.dylib 0x1def7dafc mach_msg + 24 4 libdispatch.dylib 0x1968d8f14 _dispatch_mach_send_and_wait_for_reply + 544 5 libdispatch.dylib 0x1968d92b4 dispatch_mach_send_with_result_and_wait_for_reply + 60 6 libxpc.dylib 0x21714a930 xpc_connection_send_message_with_reply_sync + 256 7 Foundation 0x18d80a3ac __NSXPCCONNECTION_IS_WAITING_FOR_A_SYNCHRONOUS_REPLY__ + 16 8 Foundation 0x18d806b14 -[NSXPCConnection _sendInvocation:orArguments:count:methodSignature:selector:withProxy:] + 2160 9 CoreFoundation 0x18eb868dc ___forwarding___ + 1004 10 CoreFoundation 0x18eb86430 _CF_forwarding_prep_0 + 96 11 CFNetwork 0x1900c71e0 -[__NSURLBackgroundSession setupBackgroundSession] + 800 12 CFNetwork 0x1900b3e80 -[__NSURLBackgroundSession initWithConfiguration:delegate:delegateQueue:delegateDispatchQueue:] + 552 13 CFNetwork 0x1900b4784 +[NSURLSession _sessionWithConfiguration:delegate:delegateQueue:delegateDispatchQueue:] + 1496 14 MyApp 0x1054210b4 CombineBgXferRepository.session.getter (in MyApp) (CombineBgXferRepository.swift:62) + 7966900 15 MyApp 0x105422fa4 CombineBgXferRepository.startUploadTask(fileURL:request:) (in MyApp) (CombineBgXferRepository.swift:310) + 7974820 If it is ok to call this uploadTask from the main thread, does this crash indicate a problem with the operating system? Are there scenarios where the background upload service does not respond to requests?