I don't think anyone except the person who banned you from the server would know so if you know who the person who banned you was you could try PMing them?
On a side note, I was also banned from that server too for some reason. One minute I was playing normally and next minute kick whenever I try to join. Just look for other servers I guess.
EDIT: In case you don't know, unless you were picked up by the cheat detection put in by NTA you can play on other servers because that's only a server ban... AFAIK.