Symptoms

Installing K2 in NLB cluster, all machines are in the same domain, all service accounts and installation accounts are in the same domain. We keep getting error the following error

"Login failed. The login is from an untrusted domain and cannot be used with Windows authentication. ---> System.Data.SqlClient.SqlException: Login failed. The login is from an untrusted domain and cannot be used with Windows authentication."
 

Diagnoses

We tried to investigate and were able to determine that the Server just needed to be re added to the domain.
 

Resolution

Please ensure that Applying the DisableLoopbackCheck on the SQL server, K2 Server and Front end Machines.
Please see the Microsoft article below regarding an alternate recommended option:

http://support.microsoft.com/kb/896861

I have seen clients where we found that the errors came from the linked server when testing it from the SQL Server. The issue was resolved after performing the following steps:-

• The custom database server seems not to be joined to the domain. Hence you unjoin and rejoin the server back to the domain.
• Please confirm is the SQL Server is also on the domain.