I was getting the Prime 2 ready to return (engineering sample) when I decided to make one last ditch effort to get the APN settings changed. I recalled I had a Textnow SIM via Sprint (totally free phone service and texting if you are in a Sprint area) which I put into the Prime 2 (no Sprint service is available at my location) but I was able to add the correct APN settings in the watch while on that SIM while it was in the Prime 2. I then removed the SIM card while the watch was on (not recommended but it worked) and put in the Tracfone SIM which then showed the ATT nxtgenphone AND the Straight Talk (tracfone) APN settings which I can now edit.
Initially I saw 1.8 Megabyte of Mobile data being used. Excited briefly … but I still can’t seem to get Internet on Mobile data. And yet it showed 1.8 Mb and then shortly after that 2.4 Mb Mobile data use. Why won’t a browser get Mobile data or the Weather App ?
In a bit more fiddling it now says 37 Megabyte Mobile data used but still can’t get Internet. ??
WOOHOO - got Mobile Data WORKING!!! Finally! I had one letter wrong in the APN settings after the tricky SIM swap (had an S instead of an A due to big fingers on small keyboard).
Even put in another SIM which previously I could not edit and could not get Mobile data on and it already had the new APN settings. So apparently a SIM card is allowed to give APN settings to the phone which it keeps once they are set.