A server error has occurred

skulla

We have installed sharepoint portal framwork and try to add NAV web parts to the site. We can access the page and view web part on sharepoint server but when we try to browse the web site on any other servers including on Middle Tier server (Navision Server) We are getting A server error has occurred, and the content cannot be displayed. Refresh the page or open a new browser window.
The event log on sharepoint server shows the following error

A server was not found at "net.[url=tcp://xxx.xxxx.xxxx:9046/TESTNAV2013/Service]tcp://xxx.xxxx.xxxx:9046/TESTNAV2013/Service[/url]". Either the URL is incorrect or the server is currently not available

We have added SPN's for service account which is running the web application and added delegation for DynamicsNAV and HOST, we have also tried to add the same delegation on the server itself but still no luck.

The service account for NAV has proper permissions and delegation, we can access RTC from all the servers including terminal server.

Anythoughts or suggestion would be great help.