Hi LingYu,
I tried
2. Remove the following folders and empty Trash:
UBF8T346G9.OfficeOsfWebHost
UBF8T346G9.ms
UBF8T346G9.Office
with no luck. I'm still getting this:
I tried to look for my current Office Licence but when I click on Office Settings I'm brought to this page:
There's no Assigned licenses section.
My previous version was Office for Mac 2011 and the version I have just installed is the same.