I think you just need a better antenna.
Fleetnet is a system designed for mobile coverage so you'll probably find coverage can be spotty.
I replaced my stock antenna with something larger and then found the sweet spot in the house for Fleetnet reception.
I'll check the geotags on the Cambridge CACC talk groups just to make sure nothing is wrong though.
Try setting your location to Arthur, ON instead of using the postal code although if it's already scanning for them, it appears your location is set correctly.