Forum:Email User limit?

Is there any limit to the use of Special:EmailUser feature? Because the second time I use it in the same day, I get an error, "Action Throttled". —  http://i151.photobucket.com/albums/s145/urbancowgurl777/UltimateSupreme2212-3.png  (T@lk) 13:48, July 2, 2012 (UTC)