neung1Most probably that VoLTE isn't enabled for your carrier. There's nothing you can do unfortunately. ASUS in your country needs to talk to the carrier and take it from there. It's a process that takes months but I recommend you to call your local ASUS and ask them
I took the sim card on the oneplus 8 pro, it can work.
In zenfone 7 pro. Dual sim menu. I can't turn 4G + 5G volte on or off.
How to Enable 4G+5G volte in thai