Hi, kindly check with your network operator if the voLTE is enabled on the sim card. Hi, we'd request you follow the below steps: 1. Clear system cache. 2. Try the same under safe mode: Hold the power button for 5 seconds => When the screen flashes with option => Press & hold power option => You will get an option to restart in safe mode 3. If still you face the issue factory reset your phone after taking a full backup.