It is showing on the 2GIG alarm panel screen.
Ok thank you for clarifying, the router is not relevant then. The message is referencing the Front Door alarm sensor.
I am not seeing any trouble condition on our end for that sensor, but loss of supervision is a general status on sensors that means that the sensor is having trouble reaching the panel with status.
General steps to troubleshoot loss of supervision on sensors can be found in the link below. In your case the first thing I would try is replacing the battery on that sensor. You can double check that the sensor hasn’t experienced any damage then too. If you still have trouble, remove it from the door and bring it close to the panel, if it still does not work when close to the panel, the sensor may need replaced.