Server unavailable or your connection has been lost

The server “net.tcp://localhost:9146/DynamicsNAV/Service” is either unavailable or your connection has been lost. Do you want to attempt to reconnect?

Shows error While opening Sales Invoice shows error and stop working. Other pages are working properly.

I get that error on pages, where I’ve made a change that NAV doens’t like. Can you roll back the last change you made to the sales invoice page??

Thnx for rply… My problem solved… I compile sales invoice list page.


go to Nav Administration tool and start the services. i think you have both version nav 2013 and nav 2016. please start or restart the services.

We have the same problem. Dynamics Nav 2009 R2, MS SQL-Server 2008 R2, MS Server 2008 R2 SP 1.
The error appears irregularly for about two weeks now. All users are affected. The error even appears when you use the RTC on the SQL-Server itself. Sometimes it is possible to reconnect immediately, sometimes the RTC closes and you have to restart it. We can’t assign the error to a specific object. There haven’t been any changes to objects in the database!

What we have already done:

  • checked windows event logs on SQL-Server and Terminal Servers
  • restarted all servers several times
  • installed latest windows updates
  • checked network traffic
  • recompiled all objects
  • checked database (normal)

Well, the most common time this occured for me, was again when I made a change to a page/table that wasn’t setup properly.

I did have this occur in NAV 2009, and like you it was a bit random, and I couldn’t find an object change that was causing the issue.

Turned out to be a permission issue on my base permission role (we had a role with the min required permissions that was applied to all users). Once we figured that out and corrected the permission, the error stopped occuring.

Might want to look there.