Problem hearing midi tracks on Cubase Element 7

Hi all, I’m having problems hearing my midi instruments in Cubase Element 7 using a Steinberg UR28m soundcard.
I can only hear midi if a create an audio track and activate the monitoring.
I can see the meters going of the midi tracks but I can’t hear the instruments. I’m talking about external synths not vst instruments.

Any help to figure it out this issue?

Thank you