Unable to upload large files with iOS

Syncing with iPhone works perfectly here, as long as the files are under a meg or so.
Once they are larger than that, they will not upload the nextcloud server. The progress display never moves, then after a minute or so it says “timed out”.

I have NextCloud 12.0.2.
iOS app is

Please check your server logfiles and use the latest version (12.0.3).