1- Download Activity Manager
2- Open the app & go to Activity list tap
3- Search for ( Modem Config )
4- Tick on the one that have ( vodafone/volte/netherla ) in its path
I used to have this issue for more than 3 months and I have tried all the available solutions
and only this one worked for me
Hello
K20PRO - xiaomi.eu ROM 11 latest stable
When I enable VoLTE it shows the symbol and the call can be made.
BUT theres is no caller ID. So I always get UNKNOWN caller, I don't even see the phone number when someone calls me.
Without VOLTE i have normal caller/number ID in MIUI phone...