Microsoft Office License or Key Issues
We are sorry for the issues with licensing your Office product.
Please make sure no other Office version is installed except the version purchased from us as this is the nearly always the cause of these type issues.
Activation will fail if you have multiple copies of Office installed.
How to remove Office on Windows
https://support.office.com/en-us/article/uninstall-office-from-a-pc-9dd49b83-264a-477a-8fcc-2fdf5dbf61d8
How to remove Office on Mac...
https://support.office.com/en-us/article/uninstall-office-for-mac-eefa1199-5b58-43af-8a3d-b73dc1a8cae3