Need help with Sapphire mixcontrol + DJ mixer

[jackrabbit]

Hi, I am having problems trying to deal with Focusrite Mixcontrol and seeking help.

I want to use an external DJ mixer so I have an audio channel with tracks on routed to outputs 1+2 and another audio channel set to outputs 3+4. Outputs correspond on back of Sapphire pro 14 with DJ mixer line inputs.

In Mixcontrol I set the channels on the left for 1/2 and 3/4. When audio is playing in Live for both channels I see blue meter lights indicating audio but whatever I do I only hear outputs 1/2.

The audio is going from the mixer to monitors so I don't need and headphone monitoring in mix control. None of the tutorials or help pages seem to cover this.