I have encountered this problem. If your problem happens locally and not on remote connection I think this can solve your problem.

I assume you have done something on the Microsoft SQL Server Surface Area Configuration tool called "SQL Server Surface Area Configuration". Go to this tool on the Start menu > Microsoft SQL Server 20XX > Configuration Tools > SQL Server Surface Area Configuration.

Then on the Services and Connections link. Check the "WinCC > Database Engine > Remote Connections" if it is using remote connections with TCP/IP and Named pipes. I just disabled the Remote connections and just changed to "Local connections only" since I still don't need remote connections. Don't forget to restart after making this change. I tried this without restarting and still received the error. But after restart it is completely gone.

This solved my problem. Please rate if this becomes helpful. I still haven't got any rating haha.

Regards to the community!