A family of Microsoft word processing software products for creating web, email, and print documents.
Hi Stanley,
Thank you for sharing the detailed information with us.
For the error message, I found a thread which has the similar issue with yours, and the member solved this error via re-assigning the license, so we suggest that you could also try it out to see the result.
If the problem persists, you can try using the Office 365 for Mac license removal tool to remove all the license on this Mac. And then sign back in the Office application with the edu account. See if issue persist.
How to remove Office license files on a Mac(please sign out all the Office applications first)
Best regards,
Jazlyn