After uploading a new version of the application in TestFlight, the application has status Processing and after several minutes the assembly disappears from the list.
Previously, there was no such problem, what could be the reason?
check the mailbox you will get a mail from Apple for that reason and if you still not got any mail so please check plist and permission in that make sure you have included all required permissions in plist.
Also, you can refer below answer: https://stackoverflow.com/questions/38498347
If you did all these steps then you should wait for some time. Build automatically in testflight.
Do let me know if it helps.