I've been trying to accept the TestFlight invitation as an internal user but each time the TestFlight application says: The invitation is invalid. Try again. If the problem persists, contact the inviter.
There does not seem to be way to resend the invitation, I tried to disable me as a tester and re-enable it but that did not make a difference.
Only option is to delete the user but I am afraid that if I delete my users from our main system account it will also kill everying else that is linked to me. How can I resend the invitation?