Can Anyone Make Sense of This Log Entry?

[Asai]

Greetings.  I've got this log entry over the past few days at the same 
time I've been getting this really strange spam from 
"worldswidedomainnames.com".  This entry is appearing 50 or 60 times per 
day in the logs:

1   Oct 30 18:59:19 triata postfix/smtp[14090]: EADE6FD8084: host 
mx.wmint.net[80.247.227.180] refused to talk to me: 554 mx4.fr.wmint.net ESMTP 
not accepting messages
I don't know if the two are related.  Does anyone have any insight 
they'd be willing to share?

--
asai