Hi mossjoan,
Thanks for posting back.
If the pop up window is still there, I suggest you input the password and click "Always Allow".
If you did, and it does not appear to solve the problem, please try the following steps to remove the Office keychain and OneDrive keychain.
a. Close and quit all Office applications.
b. Go to the Finder> Applications> Utilities> Keychain Access. Select login on the left sidebar, select "All Items", and delete all items with Microsoft and Office in the name, such as "com.microsoft.oneauth….." (right-click the item and select Delete).



c. Please restart your Mac and check again.
We look forward to your response. Thanks for your cooperation.
Sincerely,
George | Microsoft Community Moderator