Sound coming from only right monitors

So I have a bit of a unique sound system setup for my home studio. I have a Steinberg UR22c audio interface plugged into my laptop via a Usb 3.0c cable. I’m then running out of the right output (1/4inch) on the interface a 1) TRS Male to Aux Female Stereo Adapter 2) and aux to 2 rca cables adapter into the left and right channels of an amplifier. The amplifier then powers four passive monitors.

When I initially set it up sound was playing through both the left and right monitors. But now it is only playing through the right side. I have tried switching the cables on both the interface and amplifier but the signal still stays on the right. Any help would be fantastic, thanks!