Processes in Microsoft 365 for setting up Office apps, redeeming product keys, and activating licenses.
Hi,
The message that you've encountered after installing your Office 365 product can be due to an activation error. As an initial step to troubleshoot your concern, we suggest that you run the Activation Troubleshooterfound on this link. Click the Download button and follow the on-screen instruction. If you still encounter the error after running the troubleshooter, proceed with the common fixes provided on the support article.
Feel free to post back if you encounter any challenges along the process.