Processes in Microsoft 365 for setting up Office apps, redeeming product keys, and activating licenses.
Hello Hamun.Jogoo,
Good day!
Thank you for posting to Microsoft Community. We are happy to help you.
Before we proceed, I would require more information to assist you accurately.
1-Please may i know if you have followed the resolution steps via this link: https://learn.microsoft.com/en-us/outlook/troubleshoot/message-body/accept-decline-buttons-missing-in-task-request
If not, please check the resolution step via the link
2- Please may i know the type of your affected account, i mean are you using outlook.com account
The information above is very important to know the cause of your issue and provide the correct troubleshooting
Appreciate your patience and understanding and thank you for your time and cooperation.
Sincerely,
Eben Ezer Tres | Microsoft Community Moderator