Thin Client can not connect to server 2008 R2

Hello,

I have a problem with some Igel Thin Clients [Igel 2110 CE Smart].

I am able to connect to Server A (Windows Server 2008 R2 SP1) but on Server B (Windows Server 2008 R2 SP1) i get the following message:

"Because of a security error, the Client could not connect to the remote computer.

Verify that you are logged on to the network, and then try connecting again."

I am sure there is no network problem. I am able to trace and to ping, both of the servers are in the same subnet.

On Server A are only older Updated installed (about 30) on server B about 130. I don't want to uninstall all the updates.

The thin client has the latest Firmware.

Thank you for any suggestion!!