Overview
The email queue is not processed consistently and the emails are not delivered in a timely manner. Emails appear in the MailEssentials Dashboard Logs but they are not transferred to Exchange. There is enough space on the hard disk partition where MailEssentials is installed.
Solution
This behavior is caused by Exchange backpressure errors.
How to identify
On the Exchange server, open the Event Viewer, right-click the Windows application event log, and click find. Search for the word pressure. If you are experiencing backpressure errors, you will receive results similar to the following:
Resource pressure increased from Normal to High.
Resource pressure increased from Normal to Medium.
Steps
This is an environmental issue that is not related to GFI MailEssentials, and can have a variety of causes, such as insufficient space on the Exchange server, or a large mail.que file.
For more information on backpressure issues please visit Exchange/mail-flow/back-pressure.