I am experiencing exactly the same issue. For the past several days, I have been unable to install or test any of my applications through TestFlight. This has completely blocked my development workflow. All builds upload successfully, are processed correctly in App Store Connect, and appear as available in TestFlight. However, every time I try to install a build, the installation fails. Here is what I have already verified: Builds upload and process successfully. The builds appear in TestFlight. Certificates and provisioning profiles appear to be valid. I have signed out and back into my Apple ID. I have tried different devices and users. The issue affects all of my TestFlight applications, not just one. I have already contacted Apple Support, but I have not yet received a resolution. At this point, I suspect there may be an issue with my Apple Developer account, TestFlight configuration, or a backend issue on Apple's side rather than with any specific application. Has anyone had their account checked or their issue resolved by Apple? If so, what was the solution?