No, it’s not just you! TestFlight is currently down for some users, including yours truly. While Apple took a bit of time to acknowledge the issue, the System Status page has now been updated to reflect the issue.
Update: the issue has now been resolved!
According to Apple, the issue started at 8.35 AM Pacific Time and is currently ongoing. The company notes that “Users are experiencing a problem with this service. We are investigating and will update the status as more information becomes available.”
If you try to access the TestFlight app right now, you will be greeted with the following error:
A side effect of this issue is that developer builds are currently all showing as processing in App Store Connect. This issue will likely be taken care of in the next minutes, so hang tight.