This happened to my wife while on vacation. For three days she wasn't getting weather or mapmyrun on the watch to work. Not sure WHY exactly, but it fixed itself after we got out of the hotel we were in and back to a place with good network connections. Hers went a little further, in that she wasn't receiving some iMessages on her phone either, and the last day her battery was draining at an alarming rate (iPhone 6 lost 80% of battery in 3 hours in her purse, watch lost 40-50%). At the hotel, I'd tried turning wifi on off, resetting bluetooth, turning phone and watch to airplane mode and back, rebooting both, all multiple times. I was thinking I'd have to unpair and reset the watch when we got home, but once we got down the road everything started updating again. During this time, my phone and watch were working perfectly on the same networks though, so I really have no clue what was up. That was 2 weeks ago and everything's still good on hers.