Cannot start a second NAV server instance

I have one (default) instance of NAV server up and running. Then I create a second instance with the same settings but different ports. The instance creates successfully but it cannot be started. Event log gives almost no information. Version is NAV2017CU8
Any ideas about what is the problem?

From event log:

ServerInstance 'MicrosoftDynamicsNavServer$NewInstance' failed to reach status 'Running' on this server due to the following error: 'Cannot start the service.'. Additional information may be in the event log of the server.