In SQL server management studio I can see the instance - its kind of nameofwindowsserver\instancename
I tried to enter :
nameofwindowsserver\instancename : I get error “The … server cannot be found.”
instancename : I get error “The … server cannot be found.”
When I’m on the Nav Server, I can open the base in Development Environment without any problem - Ok there I can select it but the text there is nameofwindowsserver\instancename.
I do not understand why this does not work on the other server.
If you are connecting from a different machine you should verify that the firewall is not blocking the communication with the SQL Server. The SQL Server ports are not open by default.
The standard port is 1433. You can also try <ip_address>\Instance. I have seen cases where the browser service being off contributed to connection via the machine name (DNS).