Cannot receive calls from second SIM / Dual SIM not working properly

[AnakhaS]

Hi,

I own a Samsung S23 and am using two physical SIM cards in the SIM card slots.
One is by provider Mobile Vikings (MV). One is by Vodafone (VF).

I have the sim manager set to use MV for calls and VF for data.

I know both cards are working because I can make calls through MV and I can use data through VF.

However, I am unable to turn on "Dual SIM always on" and so when someone calls my VF number, it doesn't come through.

When I try to toggle "Dual SIM always on" on, I get the error pop-up "Couldn't turn Dual SIM always on on".

Any idea how I can fix this?

Thanks

[batayanlito]

Unlock sim

[pham_hni]

Is there any chances that both of your sims are 4G standby?