I had this problem with my domain, too, though of course it's not blogx or anything. I think possibly a previous owner had been A Bad Guy because it was like that from the start, though it took me several days to figure it out.
HowTo Deal With Akismet False Positives
Nutshell of the post: had a few people mark me "Not Spam" but everything I've heard mentions this "takes a while", no timeframe given.
Akismet has a contact form (NOT using Akismet, so you can request help using it when Akismet hates you!) and I made a comment on the Akismet blog, too. Later I found a contact form on Matt Mullenweg's site and gave it a shot, too.
Akismet False Positive Problem Resolved
Got a super quick response from Matt and WordPress.com support and now I'm able to comment normally. Note also that this was on the pre-Christmas weekend, so the response time was way better than I expected. I don't know how long the "Not Spam" route takes, but having somebody actually check on it seems a pretty good option.