Why Aren’t My Emails Delivered?

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If your emails fail to reach recipients, your configuration may be incorrect or flagged as spam. Common issues involve missing or incorrect SPF, DKIM, DMARC, or Reverse DNS (PTR) records. This guide explains how to fix these problems and improve email deliverability. 

Reverse DNS Check – Setting Up a PTR Record 

A PTR record (Reverse DNS) links your server’s IP address back to your domain. This proves your legitimacy to email providers. Without it, emails might be rejected. 

How to set it up: 

  1. Log in to your hosting provider’s DNS settings. 
  1. Add a PTR record for your server’s IP address. 

Contabo customers: Use the Customer Control Panel → Reverse DNS Management to configure PTR records easily. 

SPF Record – Preventing Spoofing 

SPF (Sender Policy Framework) lets you authorize which mail servers can send emails on behalf of your domain. Without SPF, email servers may treat your messages as fake. SPF ensures that mail servers can verify that your messages are legitimate. 

To configure SPF: 

  • Add a TXT record to your DNS like this: 
v=spf1 +a +mx ~all 
  • If you use an external mail relay, include it with include:. (Domain names should always be blurred in screenshots or examples.) 

DKIM & DMARC – Email Authentication & Protection 

DKIM (DomainKeys Identified Mail) adds a digital signature to emails, ensuring they haven’t been altered during transit. 

To enable DKIM: 

  1. Generate a DKIM key in your mail server settings. 
  1. Add a TXT record to your DNS: 
v=DKIM1; p=... 

DMARC tells email providers how to handle messages that fail SPF or DKIM checks and provides reporting: 

v=DMARC1; p=reject; rua=mailto:[email protected] 

DMARC reports let you monitor unauthorized email activity. 

Watch Our YouTube Video to fix email delivery issues

If you prefer a visual walk-through, we have a YouTube video on our channel ready for you: 

Conclusion 

After configuring PTR, SPF, DKIM, and DMARC, test your setup using tools such as MX Toolbox, Mail-Tester, or DMARC Analyzer: 

Check SPF, DKIM, DMARC at mxtoolbox.com 

Following these steps delivers your emails reliably and securely.

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