PC Music only playing through one channel

I install UM 2.4.6 (FreeVersion) yesterday and am having trouble splitting the inputs to my mixer. I have a Numark M1 USB. I have two usb cables from my PC but both inputs are coming through one channel.
Does anybody have any idea what the problem is.
If i need to supply more info let me know

Cheers

sounds like your PAN-control is not in the middle. Please check this.

I have checked the pan controls and they are both set to 50/50. Is this correct?

Yes, this is correct.
What do you level controls say? Do they light up for both channels?

the level controls on UM both light up and both tracks play through one mixer channel.
my mixer doesn’t have level control lights. (it’s a Numark M1 USB)

no, I means UltraMixer’s level controls. You have one level for each mono channel. That means in the mixer you’ll see 4 mono level meters.