Can find a single solutions on the internet with regards to this issue.

With YES call center help and some troubleshooting, manage to get it to work.

SIM card should be in slot 1, enable dial and data for SIM 1
Enable VoLTE (Voice over LTE).
Reboot phone and it works for me.

Probably can skip some steps but lazy to try.

Sometimes it can be because that it's(the sim card) not registered with yes sever, when there's no signal it shows emergency call only too

This post has been edited by yongtjunkit: Dec 6 2016, 10:47 PM

I see.
For my case, I actually tried disabling the VoLTE again and sure enough it cause No Service again.

Enable VoLTE and reboot, and it is back.

Maybe it's because yes is only lte only so volte needs to be on