Hi, I'm experiencing the exact same issue. I have the same error message: "Could not install {App Name}. The requested app is not available or doesn't exist." I also tried uploading new builds, removing and re-adding testers, deleting the app, restarting everything — nothing worked. What's interesting is that there were some account-related agreements to sign recently, and even after signing those and updating my account, the issue persists. So it doesn't seem to be related to the account agreements at all. It looks like this is definitely a TestFlight backend issue on Apple's side. Hoping Apple resolves this soon. Will update here if I find any workaround.