A family of Microsoft word processing software products for creating web, email, and print documents.
1
The 'Repair Now' button on that error popup dialog only performs a quick repair of the Office apps and that rarely resolves the problem with the Office apps, the best option is to perform a full online repair of your Office installation.
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 or Apps and Features
Then, scroll down to find Microsoft Office or Microsoft 365.
Select that and choose Modify - Online Repair
That should fix any issues with your Office Installation.
2
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/).