SmartPop Duplicate Delivery
Under some circumstances it is possible to receive duplicate delivery of messages.
Multiple ISP accounts
This usually occurs when a message is sent to two people and arrives at two accounts at the ISP. If you have two SmartPop accounts and they are both set to have FTGate find the recipient from the header, then each message will be delivered twice.
If you have more than one mailbox at your ISP and those mailboxes will receive mail for users at your domain, then you must configure each SmartPop account to deliver all of its mail to the specific user to whom the ISP account is intended.
For example, if the ISP account is for firstname.lastname@example.org then you must go into the SmartPop account for bob and make the following changes on the Delivery tab:
Set Mode to Manual
In Manual Delivery Settings clear the Scan Message Header and the Enable SDPS checkbox
In Delivery Failure set Default Recipient to email@example.com and for Unknown Recipient select Default
This changes should be made for all SmartPop accounts that are assigned to specific employees and should prevent duplicate delivery.