You Don't Have Permission error in Excel

I could use some help with an Excel add-in. Tiller has been reliable for some time but, today, it’s failing on my Mac laptop (don’t know about the Mac desktop yet and am reluctant to check until I debug the problem).

I’m getting an auth error (you don’t have permission to use this add-in) but that doesn’t make much sense given the account is Personal (not an enterprise or edu). I’ve cleared the cache, re-authenticated the account, and it’s still failing. The plug-in itself has vanished from the Data ribbon, although it is still available on Excel 365 (online).

Any suggestions? I couldn’t find any troubleshooting notes or similar community posts.

This is a known intermittent excel on windows error. If the problem persists after ensuring your OS and excel are both up to date, send screenshots of your version of OS and excel to support@tiller.com.