NAV 2013 Data Source issue [RESOLVED]

Hi there

I've installed new version of Jet express on a client machine and attempted to connect to a version of NAV 2013 on a server. But I am not able connect, when I click on the test conection I receive the error message:
The URL 'http://nav2013app:7047/DynamicsNAV70/WS/Systemservice' is not valid. The following error was reported: The remote server returned an error (401) Unathorized.

If I put the URL into a browser I get a login screen but I enter admin credentials and get a 400 error.

If I run the uRL on the server I get a screen showing XML

Any ideas?

Thanks in advance