Unable to Send Email Messages to Addresses on the Same Domain


Overview:
When an email message is sent from an integrated email account to another email address in the same domain, the email message is rejected and the following error appears:
 
Undeliverable message
 
This issue also occurs when the Reply To field for an email account is set to the same domain as the intended recipient.
 
 
Cause:
The email message recipient's messaging and collaboration server is detecting that the email address of the sender is different from the sender name listed in the header of the email message.   The messaging server is denying all messages from the sender of the email message due to this inconsistency.
 
Resolution:
The email message recipient must ask the system administrator to permit the following domains on the affected messaging server:
  • *.blackberry.com
  • *.blackberry.net