If you cannot send an email through your mail server, this may be because the mail server is overloaded and unable to handle the volume of messages received.
This issue can occur if someone is sending spam through your mail server, or if the qmail-send or postfix daemon, responsible for sending mail, is down. This article applies to Plesk servers on Linux.
Steps to View the Mail Queue from Your Plesk Panel
- Access your Plesk control panel.
- If you have the “Power User View” configured in your Plesk control panel, which allows you to directly access your webspaces, go to the “Server” tab and then to the “Settings” sub-tab. If you have the “Service Provider View” configured, access the “Settings” menu.
- Go to the “Mail Server Settings” menu.
- Finally, select the “Mail Queue” tab.
Steps to View the Mail Queue via SSH
- Access your Plesk server via SSH.
- To view the number of emails in the queue, we will run:
- If our server uses Postfix: mailq | grep Requests
- If our server uses Qmail: /var/qmail/bin/qmail-qstat
- To view the content of a specific email:
- Run “postqueue -p“, which will return a list of emails in the queue; the first column corresponds to the message ID.
- Run “postcat -q message_ID“
If you want to delete emails in the queue, we recommend reviewing the following article under the section “Delete emails in the queue via SSH”.