What do you mean by "doesn't search"? Are you receiving an error stating the search term is too short, or are you just not receiving any results back?

Not knowing which "star forum" you meant, I searched for "MAA" in both the Starwood forum as well as the Star Alliance forum and didn't receive any errors in either. I also didn't receive any matching results, but that doesn't have to do with the length of the search term being too short.

Our search index is incomplete, which may explain why you don't get results back for terms that you know are within a forum, but you shouldn't get any "terms are too small" errors from that.