Very weird error. He's the snapshot of the error code:
I got him to test logging in to another desktop. He logs in there with no issues. Strangely, if anyone logs into Reckon on another computer, THEN he can login to Reckon on his computer (doesn't matter which one).
They're using Reckon Accounts 2024 R1, multi-user environment.
Is the only fix to reinstall Reckon at this point?