Can and can't connect to MS SQL Server.

Hi,

i have to deal with a - for me - very strange problem:

I have two MS SQL Server, one is our productive, the other one our testing system. The connections strings I use in VS are:

Data Source=myProdServer\myProdDBMS;User ID=myUser; Initial Catalog=KMDISTRIDB;Password=MyPassword;Persist Security Info=True;
Data Source=myTestServer\myTestDBMS; User ID=myUser; Initial Catalog=KMDISTRIDB;Password=MyPassword;Persist Security Info=True;

For reasons I do not know, I can't connect to our testing server via DataGrib, the connection to the productive server is fine.

Now, I wondering what could cause the problem, as via MS SQL Server Management Studio I can connect to both systems. Does SQL SMS handle the connection in a different way? Not via TCP/IP? Is there a strange magic MS only connectivity ;-)

Any hints, where I could look for the problem and a solution are very much appreciated.

All the best,

Markus