Reply to Right side louder than left side..

Hey everyone I am new to the community .

I have a problem where the left speak is a lot quieter than the right speaker. On the actual mixer itself (Xone32) the difference is visible on the left and right dials. I have tried both decks (1210's) with the same result so it seems to me like a mixer problem. I am just wondering if there are any other reasons that this could be happening? Also if it is the mixer what could be the actual problem with it and could I fix it myself?

Any help on this would be great!

Thanks