uhm, I guess, you meant Tone Port KB37? it's bus-powered, right? bus-powered interfaces have certain limitations and commonly not found in professional recording environment because of this. if you're running power through the same USB cable you use to transfer the audio, well, bad things can happen sometimes.
why did this happen? well, an additional driver or service that you got with your other interface might worsen the things up enough to notice. next time do a system restore point before installing something to your working audio machine. there's a chance, you have one created automatically, so check this if you're sure, you won't use the new interface.
the other chance is something in cabling layout. like you've moved some cable and now monitor cable and USB cable are slightly in a different manner.
this all said, all digital stuff sometimes just goes bad. I had to replace my trusty MacBook Early 2015, as in one night it suddenly stopped bearing the real-time audio and nothing fixed it, like a clean re-install of any version of OS. what it was? IDK. maybe, the system firmware was updated.