Vortex Sound Research

EDIT: Turns out I just have to be finicky about how I put the headphone jack in. Annoying, but at least it works. Thanks for all the suggestions!

Hello. I recently purchased a Minibrute 2s, and it arrived today. When I got it working, I found that when I plugged my headphones into the headphone out no sound came out. However, when I plugged my headphones into the master out I got sound. I consulted the manual and google to no avail, does anyone know what the issue is here?