> All of a sudden the Office applications are not licensed anymore on our Remote Desktop Server
<< Do you mean that Office has been activated successfully before?
Is this shared computer activation for Office?
Please type cmd in the search bar, right-click Command Prompt and run it as administrator.
Type the following, Enter:
32-bit: cd C:\Program Files (x86)\Microsoft Office\Office16
64-bit: cd C:\Program Files\Microsoft Office\Office16
Then type cscript ospp.vbs /dstatus, Enter to check the activation status.
Then give a screenshot of the result please.
Please go to Services & subscriptions to check the license.
If nothing wrong, you could try to repair Office online.
More information, please refer to “Unlicensed Product and activation errors in Office”, methods in it may be helpful for you.
If an Answer is helpful, please click "Accept Answer" and upvote it.
Note: Please follow the steps in our documentation to enable e-mail notifications if you want to receive the related email notification for this thread.