Some of my users are stating some of the people trying to email them are getting bounce messages. I asked them to send me a sample of the block messages, and they all mostly look something like this:
Delivery has failed to these recipients or distribution lists:
Your message wasn't delivered because of security policies. Microsoft Exchange will not try to redeliver this message for you. Please provide the following diagnostic text to your system administrator.
The following organization rejected your message: mx1.888digital.com.
Sent by Microsoft Exchange Server 2007
Diagnostic information for administrators:
Generating server: edge1.rymaxinc.com
mx1.888digital.com #554 5.7.1 This message has been blocked because the return email domain is invalid.(failed to obtain DNS record for domain rymaxinc.com) ##
I believe we are on Exchange 2003 (v6.5.7638.1). Problem has been occurring since about this morning. No changes have been made on this server...