This notification can have many causes. Comment Spammers, Robotic Scrapers, Etc. Chances are if you are seeing this, your IP is blocked.
It's a PITA getting resource abuse notifications from my webhost due to hoards of unruly bots sucking up my hosting resources. Amazon AWS is one of the biggest offenders. Marketing research company's among other snoops that come racing over after a tweet is posted.
If you are a human and are receiving this notification, it's possible your IP address is blocked because it was flagged as an offender. Also If you are using Internet Explorer 8 or 9 try selecting compatibility mode. IE is a POS in my opinion.
A better more secure web browser is Mozilla Firefox. More info here on Mozilla's Website.
FidoSysop.
Source:
http://www.fidosysop.org/46365/01/justin-bieber-britney-spears-and-more-new-years-resolutions-of-the-stars/