Processes in Microsoft 365 for setting up Office apps, redeeming product keys, and activating licenses.
I had the same issue. i had 2 licences key on my computer.
1st step is to find your keys:
"Open the command line and executed the following commands:
cd C:\Program Files\Microsoft Office\Office16
cscript ospp.vbs /dstatus
Then I searched and pointed out the last 5 characters of the Office 2021 license.
Then executed this command:
cscript ospp.vbs /unpkey:XXXXX, where I replaced XXXXX with the 5 characters of my license.
And voilà."