Ijust got this bounced back to me from my server after trying to email a customer who complained about his emails are not being sent out to his customers.

SMTP error from remote mailer after MAIL FROM:<sales@******.com> SIZE=2661:
host mail.CustomerDomain.com [208.241.**.*]: 550 *.*.* This system is configured to reject mail from MyServerIP (Host blacklisted in relays.osirusoft.com)

Yes you are listed on a spam block you need to contacted

www.osirusoft.com

Okay, thank you very much for the quick response. I will contact them now.

Did you spam somebody? or not? if not they may open 25 port for you, esle you may be blocked for a long time.......

no, we pay a fortune for our search engine advertising, we don't use email for advertising, thanks