SqlException: A connection was successfully established with the server, but then an error occurred during the login process. (provider: Named Pipes Provider, error: 0 - No process is on the other end of the pipe. code example
Example: a connection was successfully established with the server, but then an error occurred during the login process. (provider: shared memory provider, error: 0 - no process is on the other end of the pipe.) (.net sqlclient data provider)
Turn out to be some SQL service was stopped somehow on server. Restarting SQL Server service manually was the solution.
I know this is foolish but worked anyway. Thanks @PareshJ for the useful comment