I'm going take you through some troubleshooting
Settings:
General management>reset >reset settings
If dont work same place reset network if that dont work make sure a toggles on in settings>connections>mobile >lte
If still dont work
FACTORY RESET.
Settings:
General management>reset >reset settings
If dont work same place reset network if that dont work make sure a toggles on in settings>connections>mobile >lte
If still dont work
FACTORY RESET.