TestFlight “Invalid code” or “Code has expired” - what to do?

TestFlight "Invalid code" or "Code has expired" - what to do?

Transcript: So, test flight invalid code or code expired. Here is some possible solution, because TestFlight is a bit buggy in Apple developer ecosystem, so some users were able to solve the problem. So this developer's account was registered as internal and external test flight tester. So then I removed myself from the list of internal and external tester, added me again only as an internal tester, got a new TestFlight redeem code and it works. So yep, that seems to be one of the solutions and it seems to work for some users.

So there are some issues:

• Like when I change the clock from 24 hours to 12 hours, I get an invalid code instead of expired, changing back to 12, that doesn't change it. So just try it out because it seems TestFlight only allows one device per external tester.
• Our tester getting the invitation has already been redeemed, Pisa requests a new invitation from the developer, even though they are signing in with the same iTunes ID. So that's just what it is. So it's only one device per external tester and you just need to know that.

In summary, if you encounter the "Invalid code" or "Code has expired" issue on TestFlight, try the following steps to resolve the problem:

1. Remove yourself from the list of internal and external testers.
2. Add yourself again as an internal tester only.
3. Obtain a new TestFlight redeem code.
4. Test if the issue is resolved and the new code works.
5. Be mindful that TestFlight may have restrictions such as allowing only one device per external tester.

Hopefully, these steps will help you successfully navigate and overcome the challenges associated with TestFlight error messages.