This is usually because your profile has come up as duplicate content. We ask that you don't use a biography on our site that you have already posted elsewhere on the internet. Reused content can negatively affect our search rankings, so it is to your benefit to rewrite your profile.
It doesn't have to be completely new. Try changing around sentences and writing others in a slightly different way. A good standard is to ensure that you don't use five or more words in a row that are the same as your other posting.