@Vimal Vala ,
The options of Security & privacy seems to be modified, please following the prompt to go to new "My Account portal" > Security info to check whether you may find the passwords set previously.
You may also try to add App password as following.
As we focus more on general issues of Office desktop applications, any issues related to Microsoft 365 account security, please ask the question in the forum below.
Microsoft 365 or Office 365 for admins
Thanks for your understanding.
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