No option for or Volte Vowifi

[ZT-5610cb21]

Please tell us some basic information before asking for help:
Model Name: ZS600KL
Firmware Version: 16.0420.2006
Rooted or not: no
Frequency of Occurrence: always
I am not able to turn on voLTE on my phone , my services provider is AIRTEL 4G.

[victor010]

Hi, we'd request you follow the below steps:
1.     Kindly check the same SIM into another slot
2.     Use another SIM and see if the same issue persists
3.     Use the same SIM in different device and see if the issue is with SIM.
4.      If still you face the issue factory reset your phone after taking a full backup : https://www.asus.com/support/FAQ/1006346/
5.      Last option would be to visit the service center
to have a check. Locate here:
https://www.asus.com/in/support/Service-Center/India

[ZT-5610cb21]

i have tried switching, but it doesn't works either, i am not getting an option to enable VoLTE.
I tried using JIO sim, and it worked.
The same SIM in different Device shows VoLTE.
I think there is some agreement that you need to do with the Airtel India for enabling 4G in this particular device.