Can't get signal for recording

I'm trying to record a DJ set with Audition CC2019/MacOSX Mojave, but I can't get an input signal.

I have double-checked that Audition has access to the microphone port in Mac security settings.
I'm using a USB audio interface (Behringer UFO202) which does get a signal (I can listen back to with headphones).
I have selected the audio interface (MMAUDIO Device) as input and output in Auditions settings, as well as on the track itself as the signal source; the i and the R button are clicked.

What could be the issue? Thank you!