Hi - I've been tracking along with a backpacking trip for a family member. He and his hiking partner had it set to update location every 2 hours, and it did that yesterday. But suddenly the updates spaced out then stopped - saw them every 2 hours yesterday, then 8 pm, 12 midnight, 4 am - and now it's 1 pm - 9 hours later - with nothing since then. I'm wondering what the technical reasons could be for a gap like this, but am having trouble finding that info on the website. Wondering about - too many trees, or battery going dead (though it's only day 2 so I wouldn't expect the battery to be dead yet?). Are those accurate? Are there others? Unfortunately the Locate and Messaging functions from my end don't seem to be working. Welcome any thoughts and ideas. Full transparency I'm wondering if I should be worried... Thanks!