I've been experiencing the same problem for two weeks. The support team is inadequate and responds very slowly. I've tried everything; I've re-tried the certificates, the users, the build, everything, but it didn't work.

same error here. Do you have any update on this?

I have the same problem. About 70 people were testing the application via TestFlight. A mandatory update was required. The application works in the simulator and on a real device. On TestFlight, I can't share it with the external group, and I encounter errors during download. I updated Xcode, renewed the certificates, reviewed the agreements, and reinstalled everything from scratch. The problem still persists. The previous working versions expired during the initial installation. It's stuck at the Ready to Submit stage. I wrote to support and am waiting for a response.