Headphone Jack

Ruled out so far:

Now the jack

• Push the plug in firmly. Half-inserted is the classic.
• Try the other headphone socket if the mixer has more than one.
• Screw the adapter down fully, or try someone else's headphones.

If none of that works you mix this set without cue. Long blends, tracks you know, watch the waveforms. The room cannot hear the difference and nobody is going to ask.

Hearing it now?

You follow these steps at your own risk. Full disclaimer.