The POP3 connector uses port 25 to progress the hanlding of email.
In order to prevent McAfee blocking the receipt of e-mail make the following changes

1. Logon the e-Policy Orchestrator Console
2. Select Directory
3. Select Policies
4. Select VirusScan Enterprise
5. Select Access Protection Policies
6. Select Settings for Server
7. Deselect Inherit
8. Modify rules, that could be
   • deselecting the port blocking option,
   • changing the port number or
   • adding VMIMB (the POP3 connector program) to the list of excluded programs.
9. Click Apply
10. Expand Directory
11. Expand Lost & Found
12. Right click Network Id
13. Click Agent Wakeup Call. This promotes changes throughout system. Otherwise wait for update process to do the promotion.