In Niagara G3, the serial tunnel service fails to start.


After installing the Niagara AX Serial Tunnel client, the service fails to start and Windows displays the following error:

Could not start the NiagaraAX Serial Tunnel service on Local Computer.
Error 1068: The dependency service or group failed to start.

Product Line

TAC I/A Series


Niagara G3

Windows operating systems (any)


The selected, virtual COM port is in use by another application or is in conflict with another service running on the Windows host computer.


Modify the COM port used by the Serial Tunnel Client.

  1. On the Windows host, go to Control Panel and double-click Niagara AX Serial Tunneling.
  2. Change the Serial Port to another selection that is not being used by other applications or services and click OK (see below).
  3. Reboot the computer