I am also having trouble with my Strive and the Geocache Navigator app. It worked for about a day and half when I installed it last summer, but hasn't worked since. I have spoken with Trimble and AT&T multiple times and they just point fingers at the other. No one seems to know why it doesn't work. My issue is that the GPS function does not work. The GPS bars were all red and it would not track. I have deleted the App from my phone, but can't seem to get it reinstalled. Still trying. As you can tell, I am very frustrated after months of this not working!
Good luck to you and please let me know how it turns out for you. Hopefully I will get mine going too.
-Mary