Fixing Common Email Delivery Problems
Email delivery issues can be frustrating, but most problems have straightforward solutions. This guide covers the most common reasons emails fail to send or receive and how to resolve them.
Emails Not Being Received
- Check your mailbox quota: If your mailbox is full, new emails will bounce. Check usage in cPanel under Email Accounts.
- Check MX records: Your domain's MX records must point to the correct mail server. Verify them in cPanel under Zone Editor or use an online MX lookup tool.
- Check spam folders: The email may have been caught by spam filters. Log in to webmail and check the Junk/Spam folder.
- Email forwarder issues: If you use forwarders, the destination server may be rejecting forwarded messages due to SPF failures.
Emails Going to Spam
- Set up SPF, DKIM, and DMARC: These authentication records are essential for good deliverability. See our dedicated guide on setting these up.
- Check blacklists: Your server IP may be on a blacklist. Use MXToolbox Blacklist Check to verify.
- Avoid spammy content: Emails with excessive capitalisation, too many links, or certain trigger words are more likely to be flagged.
- Send from a professional address: Use your domain email, not a free provider, for business communications.
Cannot Send Emails
- Verify your SMTP settings are correct: server, port, SSL, and authentication must all be properly configured.
- Ensure SMTP authentication is enabled in your email client.
- Check if you have hit the hourly sending limit (500 emails per hour per domain).
- Verify your password is correct. Try logging in to webmail to confirm.
Bounce-Back Errors
Bounce-back messages contain error codes that explain the problem:
- 550 — User not found: The recipient address does not exist.
- 552 — Mailbox full: The recipient's mailbox has no space.
- 554 — Message rejected: The receiving server rejected the email, often due to spam filtering or blacklisting.
- 421 — Temporary failure: Try sending again later; the issue is usually on the recipient's end.