ME020394 - TRB: Misconfiguration of 'POP Retrieval' can cause infinite loops


The misconfiguration of POP Retrieval can cause message looping issues with the following symptoms:

  • MailEnable's Mail Transfer Agent reports "infinite loops" having occurred.
  • Mail users will experience messages disappearing and then re-appearing momentarily


The role performed by MailEnable's POP Retrieval Connector and the POP Service are quite different. The roles of each are outlined below:

  • The POP Service is typically used by mail clients to access mail from the MailEnable server.
  • POP Retrieval is only necessary if you want to configure a mailbox to pull messages of remote/foreign pop servers into MailEnable mailboxes.

For example, if a remote mail account provided by an ISP was accessible by POP, MailEnable can be configured to pull mail from that POP Server into a MailEnable mailbox by configuring POP retrieval for that mailbox.

At a specified interval, the POP Retrieval Connector will access email from all the remote servers that have been specified and pull these messages into the respective MailEnable mailboxes.


If the POP retrieval is configured to pull mail from the MailEnable server itself, it will cause an infinite message loop.  

MailEnable will give a warning if a mailbox is configured to "pop retrieve" from itself (but does not prevent it from configuring to do so).


The POP Retrieval function of MailEnable is an advanced configuration option and should be disabled unless users have the need for their mail to be pulled from one or more remote POP servers.


For more information on configuring POP retrieval, please refer to either the MailEnable Professional or Enterprise Edition manuals.

Product:MailEnable (Pro-Any Ent-Any)
Keywords:POP Retreival Infinite Loop messages disappearing reappearing
Class:TRB: Troubleshooting (Configuration or Environment)
Revised:Wednesday, May 4, 2016