SSRS report not working under Windows authentication

Hi All

Recently I was encountered an issue with SSRS reports at sp-2016 farm, while accessing it .....its throwing an below error

If I click on manage data source -->data Source1-->Windows authentication (integrated) or SharePoint user--->Test Connection ..its showing below error message

Its working with stored creds option

Patch details

SQLServer2016-KB4037357-x64

As recommended by MS installed the mentioned patch ,but still facing the issue

The above setup was same for Test env ,but its working fine with out any issues .And hence both env's are hosted on Same domains

Request you to help me ASAP

Thanks in Advance