Outgoing Mail

• Overview
• Configuration Options
  • Smarthost Provider
  • Sender Domain
• Saving Configuration
• Testing Email Delivery
• SMTP Provider Setup
  • SendGrid
  • MailChannels
  • Amazon SES
  • Custom SMTP
• DNS Configuration
  • SPF Record
  • DKIM Record
  • Domain Verification
• Common Issues
  • Emails Not Sending
  • Emails Going to Spam
  • Authentication Failures
  • WordPress Plugin Integration
• Advanced Configuration

The Outgoing Mail tab allows you to configure SMTP providers so every WordPress site on PanelAlpha Engine sends authenticated, trackable email through a dedicated relay.

Overview

PanelAlpha Engine integrates with professional SMTP relays (smarthost providers) so outgoing email is routed through dedicated infrastructure. This improves deliverability, protects your IP reputation, and provides richer diagnostics compared to the default mail transport.

Configuration Options

Smarthost Provider

Select your preferred SMTP service from the dropdown menu:

• None — use the container's local Exim configuration (suitable for tests, not recommended in production).
• SendGrid — high-deliverability relay that authenticates with API keys.
• MailChannels — hosting-focused relay with username and password authentication.
• Amazon SES — Amazon-managed SMTP gateway with regional endpoints.
• Custom SMTP — any other relay reachable from your network; you supply host, port, and credentials.

Recommendation: Choose a smarthost provider for production workloads so PanelAlpha Engine rewrites the Exim templates and stores the relay credentials in system/exim-config.

The smarthost_provider, sendgrid_api_token, mailchannels_*, amazon_ses_*, and smtp_* keys are also accessible via the API (PUT /system/exim-config or the admin smarthost_provider fields). See the PanelAlpha API documentation (opens new window) for details.

Sender Domain

The Sender Domain field allows you to configure the domain name used for outgoing emails.

Purpose:

• Sets the domain for DKIM/SPF authentication.
• Helps maintain sender reputation.
• Required by some SMTP providers.

Configuration:

1. Enter your primary domain (for example, example.com).
2. Ensure DNS records (SPF, DKIM) are configured for this domain.
3. Verify the domain with your SMTP provider if required.

Note: Leave this field empty if you want each WordPress instance to use its own domain.

Saving Configuration

After configuring your outgoing mail settings:

1. Select your Smarthost Provider.
2. Enter the Sender Domain (if applicable).
3. Click the "Save Changes" button (green button, bottom-left).

Changes are applied immediately to all new emails sent from the server.

Security note: SMTP passwords are stored in server configuration. Treat them as secrets and restrict access to configuration files.

Testing Email Delivery

To verify your outgoing mail configuration:

1. Click the "Send Test Email" button (green button, top-right).
2. Enter a test email address.
3. Check the inbox for the test message.
4. Verify the email was delivered successfully.

If the test fails:

• Verify your SMTP credentials are correct.
• Check that your domain's DNS records are properly configured.
• Review your SMTP provider's dashboard for error messages.
• Ensure your SMTP provider account is active and has sending quota remaining.

SMTP Provider Setup

SendGrid

1. Create a SendGrid account at sendgrid.com (opens new window).
2. Generate an API key in the SendGrid dashboard.
3. Select Smarthost Provider > SendGrid and enter the API key in the SendGrid API Token field (sendgrid_api_token) in the Outgoing Mail configuration.
4. Set the sender domain (optional but recommended).
5. Configure DNS records for authentication:
   • SPF record
   • DKIM records
   • Domain verification

MailChannels

1. Sign up for MailChannels service.
2. Receive SMTP credentials from MailChannels.
3. Select Smarthost Provider > MailChannels and populate:
   • SMTP Username (mailchannels_username)
   • SMTP Password (mailchannels_password)
   • Sender Domain
4. Configure DNS records as required (SPF/DKIM).
5. Save and run Send Test Email to verify delivery.

Amazon SES

1. Verify the sender domain in the SES console and request production access if you need to email arbitrary recipients.
2. Create SMTP credentials (the IAM access key/secret pair is converted to SES SMTP username and password).
3. Select Smarthost Provider > Amazon SES and populate:
   • SMTP Endpoint (amazon_ses_smtp_endpoint, for example, email-smtp.us-east-1.amazonaws.com)
   • StartTLS Port (amazon_ses_starttls_port, usually 587 or 465)
   • SMTP Username / SMTP Password (amazon_ses_smtp_username, amazon_ses_smtp_password)
   • Sender Domain
4. Save the form so PanelAlpha Engine rebuilds Exim and persists the SES settings.
5. Run Send Test Email to confirm SES accepts traffic from your server.

Custom SMTP

1. Select Smarthost Provider > Custom SMTP.
2. Provide the relay hostname and port (smtp_host, smtp_port).
3. Enter the credentials the service expects (smtp_username, smtp_password).
4. Enable Implicit TLS only when the relay requires SMTPS (typically port 465); this sets REMOTE_SMTP_SMARTHOST_PROTOCOL = smtps in transport.conf (the exact path depends on your installation layout).
5. Set the Sender Domain so rewrite rules align with the relay identity.
6. Save and execute Send Test Email to verify connectivity.

DNS Configuration

For optimal email deliverability, configure these DNS records:

SPF Record

v=spf1 include:sendgrid.net ~all

or

v=spf1 include:mailchannels.net ~all

DKIM Record

Add the DKIM record provided by your SMTP provider (typically in DNS TXT records).

Domain Verification

Some providers require a verification TXT record to confirm domain ownership.

Location: Add these records in your domain's DNS zone configuration.

Common Issues

Emails Not Sending

Possible causes:

• SMTP credentials not configured correctly
• Sender domain not verified
• DNS records missing or incorrect
• SMTP provider account suspended or quota exceeded
• Firewall blocking SMTP ports (25, 587, 465)

Solutions:

1. Verify all configuration settings.
2. Check the SMTP provider dashboard for errors.
3. Review DNS records.
4. Test with the Send Test Email button.
5. Check server logs for error messages.

Emails Going to Spam

Possible causes:

• SPF/DKIM records not configured
• Sender reputation issues
• Content triggers spam filters
• Missing DMARC policy

Solutions:

1. Configure proper SPF and DKIM records.
2. Set up a DMARC policy.
3. Warm up your sending domain gradually.
4. Review email content for spam triggers.
5. Monitor sender reputation with tools like Google Postmaster.

Authentication Failures

Possible causes:

• Incorrect SMTP credentials
• Domain not verified with provider
• DNS propagation delay

Solutions:

1. Double-check API keys and credentials.
2. Complete the domain verification process.
3. Wait 24–48 hours for DNS changes to propagate.
4. Test with multiple recipients.

WordPress Plugin Integration

Consider using WordPress SMTP plugins for enhanced control:

• WP Mail SMTP
• Easy WP SMTP
• Post SMTP Mailer

These plugins provide:

• Per-site SMTP configuration
• Email logging
• Test email functionality
• Detailed error messages

Advanced Configuration

For advanced SMTP configuration beyond the UI, you may need to:

1. Edit server-level mail configuration files.
2. Configure relay settings manually.
3. Set up custom SMTP ports.
4. Configure TLS/SSL settings.

Consult your SMTP provider's documentation for specific requirements.

For advanced configuration, contact support.