Using Classic Outlook on Windows for personal email, calendar, and contact management
Hi Muhammad Mataal Khan,
Have a Good day.
Thank you for updates regarding your issue.
Could you please try the following steps?
· Uninstall and reinstall the new Outlook for Windows
To uninstall new Outlook:
1. From the Start menu, select new Outlook for Windows.
2. Select the arrow to expand the list option in Start.
3. Select Uninstall to begin the uninstall process.
To reinstall new Outlook:
You can directly install it from the Microsoft Store.
For more information on how to download the new Outlook for Windows click here.
If your issue still exists and not solved,
So, it seems look like backend issue.
Note: If you are not admin in your tenant, kindly contact your IT admin to perform the action
We suggest to contact your tenant admin to go to Office 365 Admin Center-> Support-> New Service Request.
The support engineers there have the correct escalation channel, and this is the most efficient way to report such issue.
You can refer to this article to check the way how to raise a ticket: Ways to contact support for business products - Admin help. The engineers in related team have higher permission and resources than us to help check the root cause from background directly.
For your reference: How do I find my Microsoft 365 admin? - Microsoft Support.
Best Regards,
Microsoft Community Moderator