Loop Feedback with outboard gear

Hi, I have a question! I recently purchased a Steinberg UR44 interface and 3 outboard compressors. All inputs and outputs go into a patchbay set as thru. I go from output 3 of the interface to the input of a compressor, and from the output of the compressor to input 3 of the interface, and I get loop feedback. This happens with all three units. How am I supposed to fix this? Why is this happening? Could you provide a solution? Thank you very much

Maybe you have Loopback set by mistake? This is enabled and disabled in DspMixFX.

Or maybe you’re monitoring the input that’s the same as the output?