Troubleshooting Email Delivery Issues: Why Emails Go to Spam

Few things are more frustrating than sending an important email only to discover it landed in the recipient's spam folder - or never arrived at all. Email deliverability is influenced by dozens of factors, from DNS configuration to email content. This comprehensive guide from SakuraHost will help you diagnose and resolve the most common delivery issues.

Common Reasons Emails Go to Spam

Email providers like Gmail, Outlook, and Yahoo use sophisticated algorithms to filter spam. Here are the primary reasons legitimate emails get flagged:

1. Missing or Incorrect Authentication Records

This is the number one cause of deliverability problems. Without proper SPF, DKIM, and DMARC records, receiving servers cannot verify your identity and may treat your emails as suspicious. Check our dedicated guide on setting up email authentication records.

2. Blacklisted Server IP Address

If the server's IP address appears on email blacklists (also called blocklists), all emails from that IP will be treated with suspicion. This can happen if another user on a shared server sends spam.

3. Poor Email Content

Spam filters analyze email content for patterns commonly found in spam messages. Avoid these triggers:

• ALL CAPS in subject lines or body text
• Excessive exclamation marks (!!!) or special characters
• Spam trigger words: "free", "urgent", "act now", "limited time", "click here"
• Large images with minimal text (low text-to-image ratio)
• Broken HTML or sloppy formatting
• Missing unsubscribe links in marketing emails

4. No Reverse DNS (rDNS/PTR) Record

A reverse DNS record maps your server's IP address back to its hostname. Many mail servers reject emails from IPs without a valid PTR record. SakuraHost configures this automatically for all hosting accounts.

5. Sending Volume Spikes

If you suddenly send a large volume of emails from a new or low-volume account, spam filters will flag this as suspicious behavior. Build your sending reputation gradually.

Diagnostic Steps

Step 1: Check Email Headers

Email headers contain detailed information about the delivery path and authentication results. To view headers in Gmail, open the email, click the three dots menu, and select "Show original".

Look for these key lines in the headers:

If any show "fail" or "softfail", that authentication method needs attention.

Step 2: Test with Mail-Tester

Step 3: Verify DNS Records

Step 4: Check the Mail Queue

If emails are not being sent at all, the issue may be with your hosting account. Contact SakuraHost support to check if there are emails stuck in the mail queue or if sending limits have been reached.

Fixing Common Issues

Fix SPF Failures

Ensure your SPF record includes all servers that send email for your domain:

Add include: entries for any third-party services (e.g., Mailchimp, SendGrid) that send emails on your behalf.

Fix DKIM Issues

In cPanel, navigate to Email > Email Deliverability and click Manage next to your domain. Click Install the Suggested Record to automatically configure DKIM.

Improve Email Content

• Use a professional HTML template with clean, valid code
• Maintain a healthy text-to-image ratio (at least 60% text)
• Include a plain-text version alongside HTML
• Always include your physical business address in marketing emails
• Add a clear, working unsubscribe link

Preventive Measures

1. Authenticate all email: Ensure SPF, DKIM, and DMARC records are properly configured
2. Monitor your reputation: Regularly check your IP and domain reputation using MXToolbox
3. Use dedicated IP: Consider a VPS or dedicated server if email deliverability is critical to your business
4. Keep mailing lists clean: Remove bounced addresses and inactive subscribers regularly
5. Warm up new IPs: Gradually increase sending volume when using a new server or IP address