Troubleshooting email deliverability issues

Troubleshooting email deliverability issues

Email deliverability depends on a series of security “handshakes” between your mybox server and the recipient’s inbox. If these handshakes fail, messages may be rejected, delayed, or filtered into spam folders. Understanding these technical layers is the first step toward building a high-reputation sender profile.

1. Verify SPF, DKIM, and DMARC configuration

To prevent spoofing and ensure trust, your domain must prove that it has the authority to send the email. This is handled by three DNS records:

• SPF (Sender Policy Framework): A text record that lists the specific IP addresses or hostnames (like mybox.com) authorized to send mail for your domain.
• DKIM (DomainKeys Identified Mail): A digital signature attached to every email. It allows the recipient’s server to verify that the email was actually sent from your domain and hasn’t been tampered with.
• DMARC: A policy that tells receiving servers what to do if an email fails the SPF or DKIM checks (e.g., “reject it” or “put it in spam”).

2. Send via SMTP instead of PHP mail()

By default, many applications (like WordPress) use the PHP mail() function. This method often produces “unauthenticated” headers that trigger spam filters.

For reliable delivery, you should always configure your application to use SMTP with your mybox credentials. This ensures every email is sent through an authorized, logged session.

Recommended SMTP Settings for mybox:

• SMTP Server: smtp.mybox.com
• Port: 587 (STARTTLS) or 465 (SSL/TLS)
• Authentication: Required (use your full email address and password)

3. Check for IP Blacklisting

If your emails are being rejected by large providers like Gmail or Outlook, your server’s IP might have a poor reputation. This can happen if another user on the same infrastructure previously sent spam.

You can check your status on professional monitoring sites:

• MxToolbox Blacklist Check
• MultiRBL

If you find that a mybox IP is blacklisted, please contact our support team immediately via the mybox panel.

4. Content and Sender Reputation

Even with perfect technical settings, the content of your message can trigger filters.

• Avoid “Spammy” Triggers: Excessive capital letters, bright red fonts, and aggressive sales language (e.g., “FREE!”, “URGENT!”, “WINNER!”) are common triggers.
• Authorized Senders: Always send from a real, existing mailbox. Using “spoofed” addresses that don’t actually exist on your domain will lead to immediate rejection.
• Link Hygiene: Ensure all links in your email lead to the domain you are sending from. Using too many URL shorteners (like bit.ly) can sometimes appear suspicious to automated filters.

5. Practical Implications for mybox Users

• Test Your Score: Before sending an important campaign, use a service like Mail-Tester. It will give you a detailed report on your SPF/DKIM status and content “spamminess.”
• Monitor Logs: If you are using WordPress, install an SMTP plugin (like WP Mail SMTP) that includes logging. This allows you to see exactly when an email left your server and if the recipient’s server acknowledged it.
• Webmail Access: If you are unsure if the issue is with your local email client (like Outlook or Apple Mail), try sending a message via mail.mybox.com. If it works there, the issue is likely in your local configuration.

Summary

Reliable email delivery is a combination of correct DNS records, secure SMTP authentication, and high-quality content. By aligning your domain with mybox security standards and monitoring your server’s reputation, you ensure your messages reach their destination. If technical hurdles persist, our specialists are available via the 24/7 Helpdesk in the mybox panel.