VoLTE HD calling function requires relevant conditions to support, please confirm by the following methods:
1. Please confirm that the VoLTE HD calling function is turned on. (5G mobile phones are enabled by default).
Path:
realme UI 3.0 & above versions: Settings > Mobile network > Sim Card 1/ Sim Card 2 > VoLTE calls
realme UI 2.0 & 1.0: Settings > Sim Card & Mobile data > Sim Card 1/ Sim Card 2 > VoLTE calls
realme UI R & Go & S & T Edition: Settings > Network & internet > Mobile network > Sim Card 1/ Sim Card 2 > VoLTE
2. Please ensure that your mobile network environment is well covered and please contact the operator to confirm.
3. The VoLTE service can only be used after it is activated. Please contact the operator to confirm that the VoLTE service has been activated.
4. Please check if you have VoLTE network coverage in your area. If not, you won’t see it on your phone. You may need to switch to a different network and try again.
5. Please reset the device and check again. For reset refer article How to reset realme mobile?
If still issue persists please contact to the nearest service center for support.
Related Articles:
What is VoLTE? How to turn it on and use it?
How to set default Calling and Internet SIM card?