If the above does not help, or different errors or behaviors occur: (You should do this even if you are 'already signed in' using those credentials.) In order to restore functionality, try the following steps:
In a Microsoft Office product (Word, Excel, etc.), the error message will appear as a banner across the top of the application window. Note: U-M Office 365 licensing applies to activate student, staff, faculty, and sponsored affiliates, but does NOT include Alumni or Retirees. NOTE: Microsoft Office 365 now requires users to log in to activate and use the applications, whereas older versions of Microsoft Office do not. Learn more, contact your admin about your Office plan.' (The error message might be titled 'Ready to View Documents') To edit, use another account to activate Office.
How to fix the error: 'Your account view documents, but it doesn't allow editing on a Mac. MacOS / OS X, Microsoft Office. Microsoft Word, Microsoft Excel, Office 365 Issue
