Microsoft Office Mac Reinstall Troubleshooting
Steps that might help reinstall

Reinstalling MS Office on Mac
Clear login identity 
 https://support.microsoft.com/en-us/office/uninstall-office-for-mac-eefa1199-5b58-43af-8a3d-b73dc1a8cae3 
 clear keychain of all MS/Office/Windows stuff

Uninstalling Microsoft Office
Go to "Finder" > "Applications" , find the Microsoft Office applications to remove and right click.
 
 Select "Move to Trash" . 
 
 
 
 Go to the Trash and empty it.
 
 
 Open up the terminal program on your mac.  You can search and find the "terminal" by clicking on the magnifying glass on the top right of your screen. 
 Then copy and paste, then run these commands in Terminal to completely remove all Microsoft Office files: 
 
 sudo rm -rf /Library/LaunchAgents/com.microsoft.*

rm -rf /Library/PrivilegedHelperTools/com.microsoft.*

rm -rf /Library/Preferences/com.microsoft.*

rm -rf ~/Library/Containers/com.microsoft.*

rm -rf ~/Library/Group\ Containers/UBF8T346G9.*