IOS 18 Safari on Mobile data network not uploading files

Question

Davx1992 OP

Created Sep ’24

Replies 11

Boosts 5

Participants 7

Hello,

I am facing a strange issue on iOS 18. After upgrading to iOS 18, I noticed the following problem:

When connected to mobile data (with Wi-Fi turned off) and trying to upload a file larger than 1MB, the connection times out. However, if I repeat the same action using Wi-Fi, everything works fine.

I have tested this issue in various ways, but nothing seems to resolve it. It appears that iOS 18 might have introduced a bug.

You can replicate the issue using this site: https://video.online-convert.com/convert-to-mp4 (Note: this is not my page, but I found the same issue here).

From the server access logs, I see successful pre-flight requests, but the main POST request never follows, which suggests that the client is not sending the request.

Boost

Answer 1

PolU3417 OP

Sep ’24

Hi, we are experiencing the same thing. When we upload through WIFI it works normal, but through 4/5G not.

2

Answer 2

BartFranse OP

Sep ’24

Hello, we are experiencing the same thing. Uploading seems to work fine on other browsers though... So it seems to be a Safari exclusive issue.

2

Answer 3

Davx1992 OP

Sep ’24

Hey all, I have also provided feedback in IOS. There is such app in beta IOS versions. With Build 5 it is still not working, and my feedback case still is open. @BartFranse @PolU3417 guys If possible submit also feedback in IOS so they pick this ugly issue as soon as possible.

1

Answer 4

Davx1992 OP

Sep ’24

Forgot to mention that on other browsers it works well both on WiFI and mobile network. My feedback case number is FB15233370.

1

Answer 5

Davx1992 OP

4w

I found how to get it working using this WA, but it is not fixed in current IOS 18 Beta 7. To get it working, I went to Safari Feature Flags, and enabled and disabled flag - Enable experimental network loader. After that, uploads started to work. From this I conclude, that it is some issue with Safari network loader. After resetting to default settings, It again didn't work, so this is workaround.

1

Answer 6

Davx1992 OP

4w

It looks that this Feature Flag - Enable experimental network loader is enabled by default, even when it is disabled. When you enable and disable it, then it is turned off. With this feature enabled, uploads from Mobile Network doesn't work, so It is a bug with this Feature Flag.

1

Answer 7

hbhalodia OP

4w

We also observed exactly same issue for multiple customers. At Akamai layer, Reverse Proxy, Application gateway it's showing 408 error.

0

Answer 8

hv02138 OP

3w

We are seeing this too. Will upvote. Uploads fail on Cellular (when using a javascript POST, selecting from image library), and work fine on WIFI.

1

Answer 9

BartFranse OP

3w

After downloading iOs 18.1 it seems to work fine again.

1

Answer 10

krzak OP

2w

It seems to be working after updating to iOS 18.1 and resetting network settings.

0

Answer 11

peterlockhart OP

5d

Updating to iOS 18.1 didn't fix it alone. I had to also go into the Safari Feature Flags and click "Reset All to Defaults". Now it works every time.

We still can't figure out an solution for our app's customers who will also experience this issue unless they each do the actions referenced above which won't happen.

1