Since 4 days TestFlight (latest version) is not working anymore - error "Couldn't load apps" shown all the time (reinstalling the app doesn't solve the issue).
iPhone SE (1st gen) / iOS 15.8.3
Several other users also have this problem.
TestFlight stopped working (error "Couldn't load apps")
Yes, many people have the same problem on the forum, technical support has not answered the question about this issue for many days. Have you tried changing your App Store account? If you change your account, TestFlight will work for some reason.