Hi Akshay,
Welcome to the community forum!
Could you please provide me with more information?
Is this only happening to this specific user, and is everyone else able to log in?
Is this related to a Sandbox?
Most of the cases, the issue is due to caching in Power BI, where the user has to clear it. You can find how to do it here: BI connector login failed - #4 by Ramazan
Warm regards,
Ramazan