Dear A K M Shamim Faisal,
Greetings! Thank you for posting in Microsoft Community. We are happy to help you.
Per your description, you have a Person or Group column in a SharePoint list, the column returns no result found when a name or email address is searched for.
For the situation you encountered, we do understand the inconvenience caused and apologize for it.
I'd like to help you, please let us cooperate, we can work together to narrow down and resolve the situation.
I tried testing in a SharePoint list, the Person or Group column works fine and can return users.
Does the issue happen when you access the SharePoint list from a specific browser? If you try a different browser such as Microsoft Edge, Chrome or Firefox, does it work?
Does a specific SharePoint list have this issue? If you try a different SharePoint list, does same issue still happen?
Do other users in your Microsoft 365 organization have this issue? It helps you check if it's a tenant wide issue.
Look forward to your reply. Thanks for your time and cooperation!
Hope you have a nice day, stay safe and healthy.
Sincerely,
Tina | Microsoft Community Moderator