Mailgun’s SMTP Relay service is a quick an easy way to have ExpressionEngine transactional emails handled through a dedicated email provider. There’s just one tiny glitch you need to be aware of. The line ending setting needs to be changed from the default \n to \r\n. That’s it. Everything else is self-evident. But in case it’s not…
In your Mailgun account, go to the Overview for your domain. In my case, I just have their default sandbox domain. You’re going to select ‘SMTP’ as your mail option and the required settings, including username and password, will be revealed.
Go to your ‘Settings- Outgoing Email’ settings in your ExpressionEngine control panel and enter your Mailgun settings
Save your settings and send a few test emails from the Communicate page.