Why couldn’t I use three ways calling / multi-conference call function? Why does it say “Unable to conference calls” when I use conference call function?

25.06.20

Three ways calling / multi-conference call function requires network/SIM card support. If your SIM card is not activated such function by your service provider, the mobile will show a message “Unable to conference calls” when you try to use it. Please contact your service provider to enable multi-conference call service for your SIM card.