Mail test failure in discourse-doctor

[sam (Sam Saffron)]

@support-bot

Suggested response:
The error message "SMTP server connection successful. Sending mail failed. end of file reached" in your discourse-doctor tests likely indicates an issue with how the Discourse environment interacts with your SMTP server during mail submission.

1. First, confirm your SMTP settings in app.yml:

DISCOURSE_SMTP_ADDRESS: smtp.mailfence.com
DISCOURSE_SMTP_PORT: 465
DISCOURSE_SMTP_USER_NAME: philion@mailfence.com
DISCOURSE_SMTP_PASSWORD: [your password]
DISCOURSE_SMTP_FORCE_TLS: true
DISCOURSE_SMTP_ENABLE_START_TLS: false
DISCOURSE_SMTP_DOMAIN: [your domain] # Ensure this matches your domain!

Adding the `DISCOURSE_SMTP_DOMAIN` setting is essential in your case. Many SMTP servers, such as Google’s smtp-relay, reject connections with `EHLO localhost`. This setting ensures that the HELO/EHLO command uses your fully qualified domain name (FQDN).
* After adding or modifying these settings, rebuild your app:

1. ```
cd /var/discourse
./launcher rebuild app

2. Test your configuration by sending test emails from the admin panel. Note: While discourse-doctor may still fail in some specific configurations due to how it bypasses the regular app email pipeline, the admin panel tests are more reliable.

Additionally, ensure your DNS records (such as SPF, DKIM, and DMARC) are correctly configured for your domain to avoid rejection from the SMTP server.

Helpful resources:

• Discourse SMTP sends EHLO localhost: Detailed explanation and solution using the DISCOURSE_SMTP_DOMAIN setting.
• Troubleshooting Email on a New Install: A comprehensive guide to diagnosing and resolving email setup issues in Discourse.
• Setting up DISCOURSE_SMTP_DOMAIN: Sample app.yml configuration file with the relevant settings.

Additional context:
The “end of file reached” message is common when the SMTP handshake fails or abruptly terminates. With correct domain settings (DISCOURSE_SMTP_DOMAIN) and rebuilding, these issues should be resolved for most configurations. However, always consult your email provider’s documentation for server-specific nuances.

This is what our auto responder came up with, I think trying smtp domain is probably worth a shot.