Hi,
553 5.3.5 http://www.blakout.info. config error: mail loops back to me (MX problem?) 554 5.3.5 <announce@xxxxxxxxxxxxxxxx>... Local configuration error
Indeed the http:// part is somewhat 'funny'. It's not supposed to be there. Check DNS settings for this domain.
As to the config error: http://www.sendmail.org/faq/section4.html#4.5. Your machine doesn't know it is supposed to accept mail for www.blakout.info (class w).
Good luck... Nico