XF 2.2 Server Error Logs: Email to {email address} failed: Unable to send mail. src/XF/Mail/Mailer.php:307

[Will Franco]

We have an SMTP relay in place through Mailchannels. When we send an email, we get dozens of the following error message:

Email to {email address} failed: Unable to send mail. src/XF/Mail/Mailer.php:307

How do I troubleshoot this issue?

 

[Chris D]

From an XF perspective, all we can do is try to send the mail and report whether it was successful or whether it failed. A failure here would indicate an issue on the SMTP end so hopefully troubleshooting from that side will give more info.

You can also test mail sending through the Admin CP. This may give back a clearer error message.

 

[Will Franco]

I can send a test email without issue. Many of the emails get delivered to the users.

Before setting up MailChannels, we had the exact same issue. Is there anything else that could be causing the issue, for example, our hosting provider/server, or is this XF to MailChannels only with no involvement from anything else?