distortioned sound with audio interface

[m21]

Hello guys. I've got big problem with audio interface that makes me really freaked out. Recently I bought KA2 and in the first two days everything was ok. I installed audio drivers etc. But now when I open my project the sound is distortioned and there's a lot of clicks and pops. The same project I used to work on few days ago with no AI was working very well but now with AI I can't do a thing. The CPU with this project is approximately 50%. I don't think that it might be caused by apps running in the background (although when I am doing something on cakewalk I only use cakewalk) because as I said, before  I started to using audio interface everything was working fine. I tried to listen to music on yt with AI and it's sounds ok. But on cakewalk it's distortioned.. (but two times I got situation that the sound on cakewalk was distortioned and it also affected the sound on yt). I noticed that sometimes I need to plugin AI a few times to make it work (maybe some problems with usb ports?). Do you guys have some idea what is the problem? What I should do? Maybe something with headphones? Adapter? USB ports? I also tried to set 2048 samples, freeze some tracks but nothing changes. I am considering  returning audio interface to the shop if it's gonna be like that. Please help me guys.