What are send errors?
The send errors are messages your email server is giving back to WP Mailster basically saying “I will not forward this message”. There are different reasons that emails get rejected from being sent.
An example is that too many emails were sent (per hour / day) so that the email quota of your hoster has been exceeded. Another example is that the hoster does not except emails with a certain content.
What does happen when send errors occur?
WP Mailster retries to send the email several times. If the send errors occur again, it will eventually stop sending.
The way this shows is the status in the email archive: a send error is indicated in the respective column:
In the above example you see that there is no check in the “Sent” column. That means the send error made WP Mailster stop sending this particular email. The remaining recipients (email instances) will be kept in the email queue.
What are my options with the current email?
You can try to continue the send process (in the hope that no new send error occur). To do so, open up the email in the email archive and click the button “Reset send errors, continue sending“.
Alternatively, you can skip the remaining recipients and remove them from the queue via the button “Remove remaining queue entries“.
How can I determine the exact cause for the send error?
You can dig deeper by opening the email in the email archive and open the “Send report” tab. Scroll down and see if you can locate the server error.
If that is not showing or only a generic message is recorded, you can enable the debug logging mode and try to reproduce the problem with the extended logging enabled. That usually results in more information being available in the send report.