Claims Authenticated web application not recognising the windows domain user

Hi,

I have migrated non-claims based web application in SP 2010 to claims based web application in SP 2013.

I have a visual webpart in one of my site collections, which fetches the logged in user and displays the user details in the visual webpart. This functionality is working in SharePoint 2010.

However, in the newly migrated SP 2013 site, the visual webpart is not working. I am not able to fetch the currently logged in user..

In the logs, I am getting the error as "unable to locate domain i:0#.w|domainname."

Has anyone come across the same issue in SP 2013?

How to fix this?

Thanks