Mac mini 2018 can't get stereo sound using interface

[wing1630]

HI,
I am using Mac mini 2018 and connecting scarlett 6i6 interface.

When I listen to a stereo music track i can hear different sound comes out from L and R channel when I use the Mac external Headphone pot as an output.

However, when I listening to the same track through headphone connecting the interface's monitor output 1/2, both L and R channel comes out the same sound (i am not sure it is a mix or either L/R channel)

How can I fix this problem?

 

[Ploki]

I don't know why people buy these interfaces.

Have you checked the routing in the software?

 

[wing1630]

I don't know why people buy these interfaces.

Have you checked the routing in the software?

I buy it for recording and mixing
Sure, the routing is fine