Symptom

When messages are downloaded using the POP Retrieval connector, a header is added to indicate how it was retrieved. The connector checks this header to see whether the email has been downloaded, to help avoid looping. If it detects the header it will log to the POPC Debug log and not deliver the email:

Message has already passed through MailEnable POP Retreiver. Message ignored. Remote Domain example.com User john@example.com

There are cases where you may wish to change this behaviour.

Resolution

To avoid the header check, add the following registry key and restart the POP Retrieval connector:

For 64bit Windows

Key Name: HKEY_LOCAL_MACHINE\SOFTWARE\Wow6432Node\Mail Enable\Mail Enable\Connectors\POP

For 32bit Windows

Key Name: HKEY_LOCAL_MACHINE\SOFTWARE\Mail Enable\Mail Enable\Connectors\POP

Value Name (DWORD): Loop Protection
Values: 1=Loop protection enabled
            0=Loop protection disabled