We have a SBS 2008 server. In the past few weeks, users have been complaining that some receipients of their emails are not receiving them sometimes. It doesn't seem to consistently be one recipient. Sometimes one recipient at a company will receive the email while others at that company will not receive email from someone else here. Here is what we have for incoming: We use Google apps. This is where our MX records point The email is then downloaded from the Google Apps mailboxes via pop3 connector to the SBS 2008 server. For outgoing: We relay email through our ISP's mail server. Our firewall is an Untangle free box doing some basic virus/web filtering. What do you think the issue could be? How do I troubleshoot this when emails just drop into a black hole? No returned messages etc.