A51 4G not working

[Lil_chris]

Hello iv recently gone from a s8 to a51 but the 4g dosnt work i have been though all the settings all are correct for 4g. Sometime After restarting my phone a couple of time i can get it on and it will stay on untill i use wifi and then turn wifi off it wont connect to 4g. 3g works fine when i go to 3g/2g only. Anyone had this fault? 

[kikasama10]

Same problem encountered,

I tried troubleshooting it by doing FACTORY RESET

From the Home screen >> Settings >> General management >> Reset >> Factory data reset >> Reset device >> Delete all.

Furthermore, we also need to remove the Google or Samsung account to ensure that the Factory Reset Protection or Reactivation Lock is deactivated.

Please go to settings < accounts and back up <account < samsung account < personal info <tap the 3 dots at the top right < sign out.