You shouldn't expect that anyone here after this brief description will be able to point out the reason of this problem, as there's many things that could cause it. Bad cables are often responsible for buzzing, but there could be many other reasons. Here's a few steps you could try on your own:
- Determine a point in time when the problem did not occur. Have you changed anything in your setup since then? Try to reverse the changes and see if the buzz is still there.
- Do it one step at a time and test after every step. For example, if you moved the location of the 2i2 and had to use a longer cable, move it back to the old spot and test before you replace the cable. If it still buzzes then replace the cable and try again.
- If the above fails (because you haven't changed anything, don't remember what you have changed, or restored everything and the problem still persists), try testing your components in isolation or different environment, or replacing them one by one. This should help you identify the faulty component.