Dual Sim always on not working

[BigHM]

I am using Samsung Z Fold 7.

Dual Sim Always On is not able to turn on

[Tourbillon De La Vie]

Are both numbers listed in full

[AndrewL]

@BigHM: Do you have 2 physical nano-SIM cards installed, or 1 physical + 1 eSIM? 

If you head to Settings > Connections > SIM manager, are both SIMs toggled on? Furthermore, if you select 'More SIM settings', is 'Dual SIM always on' greyed out?