Processes in Microsoft 365 for setting up Office apps, redeeming product keys, and activating licenses.
The solution depends on the error you are seeing in the Office apps, is there a popup error indicating the Office apps failed to start with a 'Repair Now' button, or is there a notification indicating an activation/subscription error.
1
If the error you see indicates the Office apps ran into a problem with a 'Repair Now' button:
Before performing this process to ensure you do not loose the Office installation during the repair, please log into your Microsoft account on this link (https://account.microsoft.com/services/) and check to ensure your Office licence or Microsoft 365 subscription is listed correctly on your account.
Open the Settings App (gear icon on your Start Menu)
Go to Apps - Installed Apps, then scroll down to find Microsoft Office
Select that and choose Modify - Online Repair
That should fix any issues with your Office Installation.
If that does not resolve the problem, completely uninstall Office, restart your PC, then download and reinstall Office from your account online (https://account.microsoft.com/services/).
2
If there is an activation/account error indicated in the Office apps.
Open Word.
At the top right of Word, log out of Office.
Restart (not shut down) your PC, then log back into Office, is your subscription then recognized correctly.
If not, log into your Microsoft account on this link, is your Office licence listed correctly there, or if that is a subscription, check the expiry date listed on your subscription, is that listed correctly.