I am having problems sending emails to certain email addresses. AOL.com and Optonline.com. My firewall is not blocking any traffic on port 25. All other account send fine and i can receive email from both domains as well. In the even log I see error event id 4006 "Message delivery to the host '18.104.22.168' failed while delivering to the remote domain 'aim.com' for the following reason: The connection was dropped by the remote host." Any ideas on why this is. I am running GFI mailessentials 12 on a stand alone server that is filtering SPAM for a 2000 and 2003 exchange server setup. The error is coming from the GFI machine.