Email Deliverability: Why Your Emails Hit Spam

Why Your Business Emails End Up in Spam

You spend time crafting important emails — proposals, invoices, project updates, marketing campaigns — only to discover they’re landing in your recipients’ spam folders. This isn’t just annoying; it’s costing you money. Missed proposals mean lost deals. Undelivered invoices mean late payments. Marketing emails in spam mean wasted budget.

Email deliverability is the percentage of your emails that actually reach the inbox (not spam or junk). For business emails, anything below 95% deliverability indicates a problem that needs fixing. At SecureTechs, we configure email authentication and deliverability as part of every website and domain setup we manage.

The Three Pillars of Email Authentication

Modern email providers (Gmail, Outlook, Yahoo) require three authentication protocols to trust your emails. Missing any one of them significantly increases your chance of hitting spam.

SPF (Sender Policy Framework)

SPF tells receiving servers which mail servers are authorized to send email on behalf of your domain. Without it, anyone can forge emails from your domain.

• What it is: A DNS TXT record listing authorized sending IP addresses and services
• Example: v=spf1 include:_spf.google.com include:sendgrid.net -all
• Common mistake: Forgetting to include all services that send email (your website’s contact form, marketing platform, CRM, helpdesk)
• Limit: Maximum 10 DNS lookups in your SPF record. Exceeding this breaks validation.

DKIM (DomainKeys Identified Mail)

DKIM adds a digital signature to your outgoing emails, proving they haven’t been tampered with in transit.

• What it is: A cryptographic signature in email headers, verified against a public key in your DNS
• Setup: Each sending service (Google Workspace, Mailchimp, etc.) gives you a DKIM record to add to DNS
• Common mistake: Only setting up DKIM for your primary email, not for marketing platforms or transactional senders

DMARC (Domain-based Message Authentication)

DMARC ties SPF and DKIM together and tells receiving servers what to do with emails that fail authentication.

• What it is: A DNS TXT record with your policy (none, quarantine, or reject) plus reporting address
• Example: v=DMARC1; p=quarantine; rua=mailto:dmarc@yourdomain.com; pct=100
• Recommended approach: Start with p=none (monitoring only), review reports for 2-4 weeks, then escalate to quarantine, then reject

Beyond Authentication: Other Deliverability Factors

Domain Reputation

Content Factors

• Avoid spam trigger words: “Free”, “Act now”, “Limited time” in subject lines increase spam scoring
• Text-to-image ratio: All-image emails frequently hit spam. Maintain good text content.
• Unsubscribe link: Required by law (CAN-SPAM) and expected by spam filters. Make it easy to find.
• Consistent from address: Don’t constantly change your sending address
• Physical address: Required in commercial emails — include it in your footer

Diagnosing Your Deliverability Issues

1. Check authentication: Use mail-tester.com — send a test email and get a score out of 10
2. Verify DNS records: MXToolbox.com checks SPF, DKIM, and DMARC validity
3. Check blacklists: MultiRBL.valli.org scans 200+ blacklists for your domain/IP
4. Review Google Postmaster Tools: If you send volume to Gmail, this shows your domain reputation
5. Test with Gmail, Outlook, Yahoo: Send test emails to accounts at each major provider

Action Steps

1. Test your current setup at mail-tester.com (send an email to the address they provide)
2. Check your DNS for SPF, DKIM, and DMARC records using MXToolbox
3. Add or fix any missing authentication records
4. Review your sending practices — are you warming up properly? Cleaning bounces?
5. Contact SecureTechs if you need help diagnosing and fixing deliverability issues