Resolving 'POP3 Read Failed - Connection Closed?' Errors: Troubleshooting Guide

You may receive a POP3 connection error email stating that One or more POP3 connections failed. 

It will display the following error in the details section:

Error: read failed - connection closed?

WHMCS cannot connect to the support department mailbox using the details that you set in the mail importing configuration for that department.

To resolve this error, update the mail importing configuration:

1. Go to Configuration > System Settings > Support Departments.
2. Edit the affected support department.
3. In the Mail Importing Configuration section:
   1. Ensure that the Hostname, Username, and Password are correct for the mailbox to which WHMCS should connect.
   2. Ensure that the Port value is a valid POP3 or IMAP port (typically 995 or 993).
4. Click Save Changes.