Italian version here
In December 2006 we installed a new anti-spam/anti-virus email filter.
Emails can be blocked for the following reasons:

1. the sender’s email server has been included in a blacklist of known spammers. In this case the error returned to the server is “554 Rejected as spam x.x.x.x found in dnsbl.sorbs.net” or “554 Rejected as spam see: http://spamcop.net/bl.shtml?x.x.x.x” where “x.x.x.x” is the sender’s server IP address.
   This means that this server has been included in one of the two blacklists that I am using. To remove this server from these blacklists it is needed to solve the problem and follow instructions available at sorbs.net or spamcop.net;
2. the email is considered spam based on text analysis done by the software “spamassassin”. In this case a single email can be rejected without any notification to the sender. The probability that this happens for a normal email is almost zero. It is recommended, anyway, to not send very short email messages containing only links or images.

To solve the most important problem (item 1) that prevents a user to send email to us the best solution is to solve the sender’s server problem and to have that server removed from blacklists.

If this is not possible an alternative solution is to ask us to include your server on our whitelists so that we allways accept email from your server. To do so yu need so send an email to the alternative address digiampietro @ gmail.com. If possible please provide the following information:

• attach a full copy of the “rejected as spam” error email received
• list all the email servers used by your organization to send email to us
• en email address to contact for technical issues