To resolve this:
Close any open office products
run cmd as admin
cd C:\program files\Microsoft office\office16 (or program files (x86), whatever’s relevant)
type in: cscript ospp.vbs /dstatus
this generates a list of all the license keys install on your pc. You want to look at the last line of each paragraph: “Last 5 characters of installed product key: *****”
type in: cscript ospp.vbs /unpkey:***** (whatever those 5 chars where). repeat this for every license key installed.
Once they’ve all been removed. Open an office program, sign back in and you’re done