It is probably not your account or our mail servers.

The most likely cause of problems like this are misconfigured mail servers on the sender's side or with their ISP or corporate mail server.

As part of Avvanta's Advanced Spam Protection system, we subscribe to several Realtime Blackhole Lists (RBL's). If a message is bounced back to the sender, it will tell them exactly why it bounced. The message will almost always give them a web site they can go to for more information about why their message was rejected.

The most common misconfiguration is what is called an open relay. A mail server that is an open relay will allow any computer on the Internet to send mail through it. This is one of the most common ways that spammers send out their junk email. Once a spammer finds an open relay, they will continue using it to send out as much spam as they can until the relay gets shut down.

Avvanta subscribes to four RBL lists: MAPS RBL+, the Spamhaus XBL, and Avvanta's own S.P.I.K.E. list. These are very reputable lists, and only include mail servers that are proven to be sources of spam. Exact numbers are not known, but it is estimated that between 30-50 percent of the mail servers on the Internet subscribe to one or more spam-stopping lists.

In order to get mail from that person again the administrator of the listed server will need to fix the problem(s) that got them listed. Once the problem is corrected the administrator will need to submit their server for testing and removal from the lists. Fixes for many mail servers can be found from the MAPS Transport Security Initiative pages. Avvanta will not contact the mail server administrator, nor will we provide other administrators assistance in fixing their mail server.

Another useful site to test if a particular mail server is listed is www.samspade.org, specifically the Blackhole test.