When setting up the topology using the topology builder on the Lync server, you may get the below error.
Error: An error occurred: "Microsoft.Rtc.Common.Data.SqlConnectionException" "Cannot open database "xds" requested by the login. The login failed.
Login failed for user 'MYDOMAIN\Administrator'."
Although your credentials are correct, the issue is a known bug if you are using Microsoft SQL 2008 R2. This may be fixed by installing the Microsoft SQL 2008 R2 SP 2.
Another option would also be to check the user in the error as it must have sysadmin role in the SQL server security.
Also you might need to check if you have the installed SQL Server Backward Compatibility. This is a requirment.