I have a guitar where the E and A strings have buzz. It's fine when I put a capo on the first fret, but when played open the strings buzz like a hair clipper tied to a lawnmower on the back of a truck carrying chainsaws.
Since the other four strings are ok, I'm guessing this isn't a truss ros thing, and since it's ok on every fret except the first I'm guessing it's the nut-end that is causing the problem. Could it be the fret itself or the nut that needs seeing to?
Cheers