Troubleshooting Email non-Delivery Issues with Exchange Connector

A number of factors can cause Exchange Connector to not deliver email. This article explains the most common causes and provides advice on how to troubleshoot such issues.

Check that the Service is Running

Open the Service Manager tool (instead of just checking the tray icon) and verify that the service is started. Some errors can cause the service to start and immediately stop. These problems can be identified checking the event log (see below).

Check the Windows Event Log

The next step should always be a check of the "Application" section of the event log. Any Exchange Connector errors will be listed with a source of "QSS Exchange Connector Service". Keep in mind that there could be multiple error messages, and there may be several different errors.

If you are unable to fix the error(s) in the event log after searching this knowledge base, the next step will be to e-mail the full text of all of the errors to us for diagnosis. If you can't find any errors in the event log, please see the section Further troubleshooting below.

Further troubleshooting

• Ensure that the administrator email address (on the Error Reporting/Logging tab of the Options dialog) is set to a valid Exchange email address.
• Restart the service after checking the administrator email address, as some error messages are only delivered once per start, and may have been lost.
• Perform a telnet test to the Exchange Server from the command prompt, to check the port number is correct, and connection restrictions are not preventing a connection. You can do this by typing telnet servername 25, where 25 is the SMTP server port number. If you are unable to connect via telnet, Exchange Connector will fail to connect and mail will not be delivered.
• Test the POP3 logins by opening the details of each mail and clicking the "Test" button.
• Ensure that valid recipients are selected on the Recipients tab of the Mailbox Details dialog, if "Manual Recipient Detection" is selected.
• If using "Automatic Recipient Detection", ensure that all addresses at which each user receives mail are listed on the "E-mail addresses" tab of the user properties in the Active Directory Users & Computers tool (Exchange 2003), in the user properties under Recipient Configuration, Mailbox (Exchange 2007, 2010), or under Recipients, Mailboxes (Exchange 2013, 2016 & 2019).