Environment
Device: LTE radio modules with 2G fallback
Issue
My device switched from LTE to 2G unexpectedly
The device was working normally on 4G before - but now for some reason has switched to GSM 2G/3G.
Solution
Check whether the device is within LTE coverage.
Review RAT preferences set on the device.
Cause
This can happen when LTE signal deteriorates. Most often, the device will prefer to stay on the same network before performing a full network scan and searching for other operators that offer LTE in the area.