Problem #

You receive a POP3 connection One or more POP3 connections failed error email that contains the following error:

Error: the single id was not found in response

Cause #

When WHMCS attempted to import the message, it did not exist in the mailbox.

This indicates that another program or email client was accessing the mailbox and removed the email at the same time as WHMCS.

Solution #

When sharing a mailbox between devices and programs, use the IMAP protocol on each of them.

Last modified: June 14, 2024