Microsoft Lync Error: Microsoft.Rtc.Common.Data.SqlConnectionException Cannot open database xds requested by the login. The login failed. Login failed for user Domain\administrator.

Error:

An error occurred: microsoft.Rtc.common.Data.SqlConnectionException Cannot open database xds requested by the login. The login failed. Login failed for user CONTOSO\administrator.

When Installing lync there is automatically added a firewall rule that opend the port for the sql server Service

Solution:

Create a windows Firewall port exceptions to enable access to the SQL Server Browser service, follow these steps:

1. Click Start, and then click Control Panel.
2. Open the Windows Firewall program.
3. Click change Settings to open the Windows Firewall Settings dialog box.
4. Make sure that Windows Firewall is turned on, and then click the Exceptions tab.
5. Click Add port to open the Add a port dialog box.
6. Enter a name for the port exception, such as SQL Server Browser Service.
7. Make sure that UDP is selected, and then enter UDP port number 1434. This is the default port that the SQL Server Browser service listens on.
8. Click OK two times to close the Windows Firewall Settings dialog box