Same issue here, I been at it with FCA, Dealerships, yes 2 different dealers and XMGuardian. My problem started when I purchased the map update in December, which came with a uConnect update. After updating uConnect 12 system, Nav won't update, and I lost access to in-vehical SOS and Assist button along with Online Nav Search and Voice Search. All of this is broken. When I press SOS it says I don't have an active subscription, when I press Assist same problem, I don't have active subscription and if I try to use the Send & Go app on the screen same issue, don't have an active subscription. I have gone around and round with everyone, no one knows what is wrong or how to fix it. The App works fine, I can send lock/unlock, find vehicle, send directions from the phone, all gets received in the vehicle but nothing in the vehicle works.
I finally had some success, after getting the dealer to replace the electronics unit, which didn't fix the problem, I called FCA Here Maps Update support and complained to them and finally got someone who is actually knowledgable. Turns out, atleast what they say, there are reports from a number of RAM's that run into this issue after the v39.x update/nav update and currently they have suspended sales of nav update until they figure this out. Right now i'm SOL and told, hang tight as we work with XMGuardian and come up with some solution to resolve this issue.
So if you have this problem, active XMGuardian, but in-vehicle SOS and Assist buttons do not work, Send & Go says no active subscription, navigation online search is disabled and you are unable to use voice search either, then you are in the same boat and I recommend you call FCA support and reach out to Here Maps support people as they seem to know more than anyone else. I am now on my 5th case reported and at some point, it may be time to pull the old lemon law out...