Messages deleted using a POP3 client reappear


SYMPTOMS

When deleting messages via a POP client and the client is refreshed the deleted messages reappear.

CAUSE

The problem is more evident when using a POP3 clients on mobile devices as they are more prone to network disruptions. The issue is that the messages are marked for deletion by the client but a QUIT command is never issued to the server.  The server expects a QUIT command from the client in order to delete the messages that have been marked for deletion in the POP conversation. Inspecting the MailEnable POP log files will help identify this behaviour (https://www.mailenable.com/documentation/10.0/Standard/POP_Logging.html). An example of a log extract can be found below:

02/23/18 17:56:47 POPS 1484 127.0.0.1 DELE DELE 462 +OK 0 10

For the above example there is no QUIT command after the DELE for that POP conversation. An easy way to determine this is by searching the log file after the above line using the criteria socket number and IP address.

Example: 1484 127.0.0.1

Also, inspecting the associated POP debug log file for the same time, socket number will provide more information if there were errors reported relating to the QUIT command or if the client simply disconnected because of a network disruption.

RESOLUTION

If this problem is experienced then the recommended protocol would be to switch the device to connect via IMAP. This will leave the messages on the mail server. When the client deletes a message, it is marked for deletion and shortly after removed from the server when an EXPUNGE command is issued by the client. The difference here is that if the client disconnects the message has always been flagged for deletion on the server. If there is a network disruption between the client and server the client will still be in sync and not display the deleted message.

Another approach would be to delete smaller amounts of messages or use another email client to delete the messages. I.e: the MailEnable Web mail client.



Product:MailEnable (All Versions)
Article:ME020684
Module:POP
Keywords:POP,delete,reappear,mobile
Class:PRB: Product Problem or Issue
Revised:Wednesday, March 28, 2018
Author:
Publisher:MailEnable