To solve the activation problem, please follow the steps below:
- Choose Force Quit from Apple menu to close all MS Office Applications
- Download and run the License Removal Tool by following the guideline at https://support.microsoft.com/en-us/office/how-to-remove-office-license-files-on-a-mac-b032c0f6-a431-4dad-83a9-6b727c03b193
- Remove the following files from your Mac (You will need local admin privileges to make changes to your Keychain Access):
- Go to Finder => Applications => Utilities => Open Keychain Access.
- In Keychain Access, delete the following files: – Microsoft Office Identities Cache – Microsoft Office Identities Setting – Microsoft Office Ticket Cache
- RESTART your Mac and open any Microsoft Office applications for reactivation.