Stock S4Active - Loses Network Until Airplane On/Off
I've got a stock, unrooted Galaxy S4 Active. Recently I've been having a lot of trouble with it...
Long and short of it is, at some random, arbitrary point, it will lose all service - internet, calling, GPS, and text messaging - until I turn airplane mode on and off again. Then it immediately begins to work again, only to lose all service at some random point again. It could work fine for up to two days, or it could work for 20 minutes or so. I'm baffled.
It never seems to "lose service" while actively being used, though that could simply be luck.
Sometimes GPS works, sometimes it doesn't.
It never "turns back on" on it its own - ever. Only a hard reset or an airplane mode toggle will fix it.
It doesn't SAY that it's out of service - for all intents and purposes, it looks like it's working fine. It's only when you try to USE one of the services and they don't work that you notice something's up. For this reason, I couldn't use Tasker to automatically airplane on/off based on network availability.
While it isn't working, calls to it go straight to voicemail.
After an airplane mode toggle, I immediately receive all missed texts and missed call notifications.
What I've tried:
Upgrading versions OTA via AT&T.
Downgrading versions via AT&T's files, via USB.
Changing the APN (though I MAY have done this wrong/not changed it correctly, and after it didn't work any better, I removed the added APN).
If anyone can help, I'd be extremely grateful. Thanks!