What are email delivery problems and how can they be solved?

In some cases, you might encounter email delivery issues when sending your messages. You draft your email, personalize it, select your recipient(s), but the delivery is not ensured as expected.

Sending can fail because of credentials, the SMTP submission server, DNS, restrictions or the recipient server. Read the error response to identify the cause.

Common Email Delivery Issues

Authentication Issues: SMTP authentication uses mailbox credentials. SSL/TLS encrypts the connection; it is a separate function. Check both settings. SMTP Settings: The issue might simply be with the email settings you've configured. Ensure you are using the correct settings. Expired Domain Name: If your email address is linked to your domain name, confirm that your domain name is not expired. Port Issues: The SMTP server commonly uses 587 with STARTTLS or 465 with implicit TLS for client submission. Follow the service’s settings; port 25 may be filtered by someInternet Service Providers) block port 25. Antivirus or Firewall Issues: Ensure that your firewall, proxy service, or antivirus software has an exception rule for the SMTP service. Blocked IP Addresses: If an IP is blocked, ask support to check the rule and cause before changing an whitelist . A recipient’s IP is not necessarily their mail server’s IP; arbitrary allowlisting does not fix the problem. IP Frequency: If you frequently send emails to a specific recipient and they classify them as unwanted, the system may temporarily block your IP address, treating your emails as spam. If you continue to experience issues with email delivery, feel free to open a new ticket to contact our support.

Check the result and troubleshoot

SPF, DKIM and DMARC must reflect actual authorized senders. Do not create multiple separate SPF records at the same name. If another provider manages DNS, publish the records there; cPanel’s Repair button cannot update an external zone by itself.