Mystery_Flasher
Android Enthusiast
Just checked all those settings and they're all (apparently) as they should be. It's actually been fine since last night and just started acting up again a few minutes ago.
You should still try what I said

The thing is, removing and creating apns again may actually help. It helped me and some other people from here. I know it sounds silly but checking those apns if they are correct is not enough. You need to actually remove them and create them from scratch. It's worth to give it a shot.

Might be helpful to some people. 