Server Fault is a question and answer site for system and network administrators. Join them; it only takes a minute:

Sign up
Here's how it works:
  1. Anybody can ask a question
  2. Anybody can answer
  3. The best answers are voted up and rise to the top

This question already has an answer here:

Having some problems with mail messages which are rejected as spam when sent directly to a user at a certain company address but if that users sends us a message and we reply, it is accepted. If I try connecting via smtp on command line from our server, the connection is received. Any ideas why a direct message is rejected as spam?

share|improve this question

marked as duplicate by Greg Askew, growse, voretaq7 May 22 '13 at 18:15

This question has been asked before and already has an answer. If those answers do not fully address your question, please ask a new question.

You need to ask the admin of that company, no one here can say what they're running or what policies they have in place. – NickW May 22 '13 at 15:47

Quite a few spam filtering systems rank incoming e-mail lower if it references e-mail that was send from the receiving organization. The replying party adds a In-Reply-To: header referencing the original e-mail to the message. A quick lookup verifies the reference and mail gets through.

Your original e-mail is probably marked as spam for one or more of the most common reasons:

  • Forward/Reverse DNS and HELO/EHLO improperly configured
  • SPF record wrong/missing/etc
  • IP Reputation (DBSBL, SenderScore, and similar)
  • Your sending spam (or something that look a lot like spam)
share|improve this answer

Not the answer you're looking for? Browse other questions tagged or ask your own question.