My PDB file has some image miss-match issue. I tried to have correct file in correct places. Then error status change to An error occurred while attempting to add the account. A network-related or instance-specific error occurred while establishing a connection to SQL Server. The server was not found or was not accessible. Verify that the instance name is correct and that SQL Server is configured to allow remote connections. (provider: SQL Network Interfaces, error: 25 - Connection string is not valid) But still cannot add users into database.