Dear Adrian Paul Olescu,
Greetings! Thank you for posting in Microsoft Community.
I'm sorry to hear that you're having trouble signing in to your Microsoft account and activating Microsoft Office.
As far as I know, Error code 80072F8F usually indicates a problem with the date and time settings on your device. So, please make sure that the date and time on your device are correct and match the current time zone.
You may also try using Microsoft Support and Recovery Assistant to troubleshoot Office activation issue.
You can download the tool from this link https://aka.ms/SaRA-OfficeActivation-sarahome
If issue still happens, I understand how frustrating this situation can be and sincerely apologize for the inconvenience caused. Let me help you further. I would appreciate if you could share following information:
1.Could you please share a screenshot of the error?
2.May I know the version of your Office? Please open Control Panel > Programs > Uninstall a program. From the programs list, capture a screenshot of your Office.
We look forward to hearing from you; Please understand that our initial reply may not always immediately resolve the issue. However, with your help and more detailed information, we can work together to find a solution.
Thanks for your cooperation and understanding. I hope that you are keeping safe and well!
Sincerely,
Tina | Microsoft Community Moderator