Accessing DFS Share from a Trusted Domain

I have a Windows 2012 R2 server in domain D. This is the namespace server for the namespace D2.

From other machines in domain D I can access \\D\D2 ok

I have machines in another domain - domain U. There is a two way trust between domain D and domain U.

I am trying to access \\D\D2 from a Windows 2003 server in Domain U but am getting the message:

"Configuration information could not be read from the domain controller, either because the machine is unavailable or access has been denied"

I was under the impression this should work as there is a trust in place.

Has anyone any suggestions please?

Thanks