I have added a new server registration and all is running fine for this new instance and the app that uses it.
However, I open QA and I connect to server X and run....
select * from y.myTable (Y is the new instance)
and I get the error...
Server: Msg 18452, Level 14, State 1, Line 1
Login failed for user '(null)'. Reason: Not associated with a trusted SQL Server connection.
Both servers have windows and sql authority.
I am logged on as myself and am a member of SA on both boxes.