Mac headphones not working

Hi all. Pls forgive me if this question has already been addressed, I haven’t been able to find a solution.
I’ve a MacBook Pro with Mojave, Steinberg UR22 MkII and Cubase 8 Elements. When I try to hear a project w/o UR22 I can hear the output from the Mac’s loudspeaker, but if I try to hear from headphones I can’t hear anything.
If I’m hearing from Deezer, Spotify or YouTube the headphones work normally.
So I think it’s a configuration in Cubase, but I haven’t been able to figure what kind of configuration it is.

Pls help me.
Saverio Tedeschi