How to troubleshoot email delivery problems

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Troubleshooting Email Delivery

If your emails are not being delivered or going to spam:

Step 1: Check DNS records

  • Verify your MX records point to mail.yourdomain.com
  • Ensure SPF record exists (TXT record starting with "v=spf1")
  • Check that DKIM is enabled in cPanel > Email > Email Deliverability
  • Verify DMARC record is published

Step 2: Check for blacklisting

  • Use the RBL lookup tool in the Tools section of the client portal
  • Check your server IP against Spamhaus, Barracuda, SORBS, SpamCop
  • If blacklisted, follow the delisting process for that specific RBL

Step 3: Check email logs

  • Review bounce-back emails for error codes
  • Common error codes:
    • 550 - Sender verification failed (check SPF/DKIM)
    • 554 - IP blacklisted
    • 421 - Server temporarily unavailable
    • 535 - Authentication failed (check password)

Step 4: Contact support

If you have checked all of the above and still have issues, open a support ticket with:

  • The email address affected
  • The recipient's email address
  • The bounce-back message or error
  • Approximate time the issue started

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