Mission Planner UAVCAN SLCAN not working

I’m trying to use UAVCAN within Mission Planner to allocate a node id to a HERE2 GPS that’s connected to the CAN1 port (I also tried CAN2). I’m following the instructions here:

When I click on “SLCan Mode CAN1” (or “SLCan Mode CAN2”), the buttons gray out but nothing happens. I’m not getting the HERE2 device info. Any help would be appreciated.

A few more details:
Running Mission Planner 1.3.68 build 1.3.7105.26478.
Uploaded latest Copter firmware per the instructions above.
Using USB cable to connect Windows laptop to Pixhawk2.1 with Cube Black.


Whoops, my CAN bus was disabled. I found that out by watching an excellent YouTube video here:

Good to go. Thanks everyone.