Reply to cue sound not working

guys i'm in desperate need of some assistance..

I went to practice on the s4 today and the sound from the master outputs in my speakers play normal, however my headphone cue is giving me no sound.

Before any advice is given however, here is what i have already tried..

The audio device is set to the s4. It is in internal mixing mode.

Master out is set-up correctly, cue is set to the settings it should be set too.

The volume on the controller itself for the cue is turned up to where you could hear sound if it worked.

The headphones do work i tried them in my laptop without the s4 and they played normal.

I have shut down my MBP, unplugged the s4, restarted and replugged the s4 back in and then booted traktor back up only to see the same issue.

This is a huge nuisance for me at the moment, i have done a Google search and had no luck on an answer. Any advice would be awesome at this point. They did work only a few days ago i have no idea what could have caused the outage. There appears to be no physical damage either to the headphone jack.