I jave a domain admin user – can login to SQL server 2016 through RDP, and can connect to SQL using Windows credentials in SQL Server Management Studio (SSMS).

Got a non-domain admin user, but he is part of local admin group of the same SERVER.- can login to SQL server 2016 through RFP, but cannot connect to SQL using windows credentails in SSMS.

In sql event logs/event viewer it shows

Login failed, no login names found

HOw do I fix this and make non-domain admin user to connect without giving him domain admin rights?

checked error logs in sql:

error 18456