Chief executive and deputy chairman Paul Barber said: "We have made clear our zero-tolerance policy many times over, and there is no excuse for abusive and offensive comments being posted online.
"We expect all our supporters to adhere to some basic levels of respect, as the vast majority do, but those who choose not to will be faced with sanctions such as these, and, where appropriate, criminal charges and prosecution.
"In this instance, we thank those of our supporters who highlighted the posting to the club. As a result, the individual concerned has had their season-ticket cancelled and a two-year ban imposed.
"We have stopped short of naming the individual or highlighting the post, and we would request others to do the same, as we do not wish to further highlight the behaviour or cause additional offence."