Can hear through speakers but not headphones.

Alright so the way i currently have this set up is i have a U-Mix Control Pro. The output is plugged into Output 1/2 LR and plugged into my speakers AUX jack. the thing is i can here everything just fine through the speakers but i cannot for the life of me hear through the headphone jack in the front. the mix and level are where i want them to be but i cant hear anything. it use to work before the 3.0 update.