Zoom B1 four -> DI -> dead?

Newbie question here — I love my Zoom B1 four, and I have it running through either a Joyo Tidal Wave or a Celine CP-60 Wine Cellar to the mixer. It all works pretty well except that it sometimes just cuts out the volume to where I’m not getting much of the signal through the speakers. It’s especially true when I play any distortion sound on the Zoom. Last night, I heard a faint signal of all distortion without any low frequencies. We checked the mixer - there’s no Low Pass Filter cutting things off. What am I doing wrong? Also, what’s a good way to get a better grasp on how these pedals all operate?