I cannot comment on other blogs by wordpress account

It seems like my e-mail address was flagged as spammer by wordpress. I didn’t notice it until a blogger friend informed me that my comments are sorted into spam list. It is strange because I used to comment by the same email address before and there was no problem. I never left a lot comments on multiple sites in short period of time. But now it looks like my comment never shows up.
Is there anything I can do to fix it?