2.2.1 not recording audio

I’m running Audacity 2.2.1 on a macbook air (os x 10.13.3) with a pioneer djm-s9 mixer. I have the rca connectors plugged into the mixer’s audio out and the 1/8" end plugged into the macbook’s headphone jack but for some reason I’m not able to record audio. Any help is appreciated. thanks!

While you can force that to work poorly, it’s likely to need special purpose sound adapters, it’s easy to overload, clip and distort and it’s mono, not stereo.

I use the Behringer UCA-202 on my Air.

It will plug into either computer type. That’s my stereo mixer on the right.

My earlier MacBook Pros don’t need it because they have real stereo recording connections (on the left).