LTE coverage intermittent in same location

[Android Central Question]

I have a Samsung Galaxy S8. It has worked well for the past 6 months or so. More recently it has decided to stop using wireless data. MMS services typically do not work. I can force them to work by turning airplane mode on and off which forces an LTE/4G connection that stays on until the phone goes to sleep. My data works when it is connected, it just does not connect all the time. 19 days of use resulted in 38Mb of data used which low enough to be nothing. Data also works with tethering and this email is being sent from a laptop connected through a wifi tether to my phone. Is there a setting that needs to be adjusted to make this work again? It seems like after the phone locks it is terminating the network coverage and is not able to recover that setting when I unlock it. I look forward to your help.

 

[Rukbat]

There's no setting that allows the hotspot app (whether it's part of Android or an external app makes no difference) to work, but other apps to not work. Possibly reflashing the ROM would fix the problem, or possibly there's a hardware issue. (And flashing the ROM wipes everything you've done since you got the phone, so you have to have everything backed up.)

Flashing a Samsung is almost trivial, though - see [Samsung] How to flash Stock ROM via ODIN. (And don't die of boredom - wait until there's a good TV show to watch while the phone sets itself up, or you'll be watching grass grow in the Arctic in the winter.)