Weird error with HTTPS connection

I have a weird problem with HTTPS connection.

Task <A19A5441-F5CD-4F8C-8C88-73FC679D8AE0>.<1> finished with error [-1200] Error Domain=NSURLErrorDomain Code=-1200 "An SSL error has occurred and a secure connection to the server cannot be made."

I am trying to bypass server certificate of my website because it's self-signed.

The following code works in a test app, but not in another app. They have exactly have the same entitlements:

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
<plist version="1.0">
<dict>
	<key>com.apple.security.app-sandbox</key>
	<true/>
	<key>com.apple.security.files.user-selected.read-write</key>
	<true/>
	<key>com.apple.security.network.client</key>
	<true/>
</dict>
</plist>

    func urlSession(_ session: URLSession, didReceive challenge: URLAuthenticationChallenge,
                    completionHandler: @escaping (URLSession.AuthChallengeDisposition, URLCredential?) -> Void)
    {
        let protectionSpace = challenge.protectionSpace
        guard protectionSpace.authenticationMethod == NSURLAuthenticationMethodServerTrust,
              protectionSpace.host.contains("mywebsite.net") else {
            completionHandler(.performDefaultHandling, nil)
            return
        }

        guard let serverTrust = protectionSpace.serverTrust else {
            completionHandler(.performDefaultHandling, nil)
            return
        }

        let credential = URLCredential(trust: serverTrust)
        completionHandler(.useCredential, credential)
    }


    @IBAction func testMenuItem_select(_ sender: Any) {
        print("\(sender)")
        Preferences.instance.openTipShowed = false
        testURLSession()

        func testURLSession() {
            let session = URLSession(configuration: URLSessionConfiguration.ephemeral,
                                     delegate: self, delegateQueue: nil)
            
            let url2 = "https://www.mywebsite.net/spiders.txt"
            let url3 = "https://www.apple.com/"
            let url = URL(string: url2)!
            var request = URLRequest(url: url)
            let task = session.dataTask(with: request) { data, response, error in
                if let error { print(error) }
                if let data {
                    let text = String(data: data, encoding: .utf8)
                    print("HTTP response object:", response ?? "")
                    print("HTTP resonse text:", text ?? "<empty response>")
                }
            }
            task.resume()
        }
    }