Using Classic Outlook on Windows for personal email, calendar, and contact management
Hello Sudip Manna,
Thanks for posting on Microsoft Community.
Based on your description, may I carefully confirm with you, which Outlook version you are using? Could you please provide us a screenshot via open Outlook desktop client File > Office Account?
Note: To avoid your personal information expose, please hide names and email addresses.
Please have a try with scenarios list below to do whether check issue persist:
Run Outlook safe mode, you could refer Open Outlook in safe mode (microsoft.com) to know more details.
Repair Outlook, please check with our official article Repair an Office application (microsoft.com).
Run Microsoft Support and Recovery Assistant, you could refer About the Microsoft Support and Recovery Assistant to know what is SaRA tool and how to download and use it.
Your time and co-operation will be highly appreciated.
Kind Regards,
Tommy