--- title: "Why Emails Go to Spam (Real Causes + Fixes)" description: "Learn the most common reasons cold emails land in spam and how to improve email deliverability, inbox placement, and sender reputation." url: https://help.salesforge.ai/en/articles/10333594-why-emails-go-to-spam-real-causes-fixes collection: "Deliverability & Compliance" updated: 2026-11-05 language: en --- # Why Emails Go to Spam (Real Causes + Fixes) Learn the most common reasons cold emails land in spam and how to improve email deliverability, inbox placement, and sender reputation. Even with properly configured domains and mailboxes, cold emails can still land in spam. Modern ESPs like Gmail, Outlook, and Yahoo evaluate many signals before deciding whether an email belongs in inbox or spam. Spam placement is usually caused by a combination of: - Mailbox reputation - Domain reputation - Sending behavior - Email content - Recipient engagement - Technical setup In most cases, it is not caused by a single issue. ## Most Common Reasons Emails Go to Spam ### 1\. Mailboxes are not properly warmed up New mailboxes have no reputation. If you start campaigns too aggressively before warming up, ESPs may flag your emails as suspicious. **Fix** - Warm up new mailboxes for 2 weeks with warm-up emails only and no cold emails. Warm-up starts at around 3-4 emails per day and reaches 20 per day by the end of week 2 - Keep warm-up enabled continuously, also after you start sending cold emails - Increase cold sending volume gradually, up to a maximum of 30 cold emails per day per mailbox Pre-warmed mailboxes still require ongoing warm-up activity. For the full timeline, see [Cold Email Warm-Up Best Practices](https://help.salesforge.ai/en/articles/10333596-cold-email-warm-up-best-practices-daily-limits-ramp-ups-and-why-warmforge-matters.md). ### 2\. Your email copy triggers spam filters This is one of the most common causes. Even with healthy infrastructure, repetitive or overly salesy copy can trigger spam filters. **Common causes** - Repetitive messaging - Too many links - Aggressive sales language - Overused signatures - Lack of personalization - Heavy formatting or images **Fix** - Use personalization and spintax - Keep emails short and natural - Reduce links and tracking - Rotate signatures occasionally - Write conversational emails ### 3\. Links inside the email are blacklisted If your email contains blacklisted links, ESPs may instantly send the message to spam. **Fix** - Remove links and test again - Avoid URL shorteners - Use custom tracking domains - Check domains using blacklist tools **Useful tools** - MXToolbox Blacklist Check - Mailmeteor Spam Checker - Mail Tester ### 4\. Sending volume increased too quickly Sudden spikes in sending volume are a major red flag. **Fix** Scale slowly over time, and stay within 30 cold emails per day per mailbox. Example for a new mailbox: - **Weeks 1-2:** warm-up only, ramping from 3-4 up to 20 warm-up emails per day, no cold emails - **Week 3:** start with 15-20 cold emails per day, with warm-up still running - **Week 4:** build up to 30 cold emails per day, plus 20 warm-up emails (50 in total) Avoid aggressive scaling on new domains. To send more, add more mailboxes and domains instead of increasing the volume per mailbox. ### 5\. Low engagement signals If recipients ignore, delete, or mark your emails as spam, your reputation declines. **Fix** - Improve targeting - Personalize emails deeply - Focus on reply rates instead of volume ### 6\. Poor technical setup Missing or incorrect DNS records can hurt deliverability. The important records are SPF, DKIM and DMARC. **Fix** - Verify all DNS records - Use secondary domains for outreach - Avoid too many mailboxes per domain ### 7\. Sending to lookalike domains Sending test emails between similar domains can trigger phishing protection. **Example** If your domain is [companyhq.com](https://companyhq.com), avoid testing with: - [company-hq.com](https://company-hq.com) - [companymailhq.com](https://companymailhq.com) **Fix** Use unrelated domains for testing. ### 8\. Poor lead quality or invalid contacts High bounce rates damage sender reputation quickly. A healthy bounce rate should generally stay below 3%. **Fix** - Validate contacts before sending - Remove invalid leads regularly - Avoid outdated databases ### 9\. Recipient-side spam filters Some companies use aggressive internal spam filters. This is common with enterprise companies, government organizations and financial institutions. **Fix** - Simplify content - Reduce links - Avoid attachments - Use plain-text emails ## How to Diagnose Spam Issues ### Step 1: Send manual test emails Login directly into the mailbox and send emails manually. If manual emails land in inbox but campaign emails go to spam, the issue may be related to: - Email copy - Tracking links - Sending platform settings - Sending IPs ### Step 2: Remove content gradually Test your sequence by removing elements one by one. For example: - Remove links - Remove signature - Remove images - Simplify wording - Reduce formatting This helps identify the exact trigger. ### Step 3: Use spam testing tools Recommended tools: Mail Tester, Mailmeteor Spam Checker and MXToolbox Blacklists. These tools help identify: - Blacklisted domains - Missing DNS records - Spam-triggering copy - Reputation problems ## Best Practices to Stay Out of Spam **Infrastructure** - Use secondary domains - Configure SPF, DKIM, and DMARC correctly - Limit mailboxes per domain **Sending behavior** - Warm up new mailboxes for 2 weeks before sending cold emails - Warm up continuously, even after you start cold sending - Send up to 30 cold emails per day per mailbox, and scale slowly - Avoid volume spikes - Keep bounce rates low **Email copy** - Personalize emails - Use spintax - Keep emails short - Reduce links **Lead quality** - Validate contacts - Target relevant prospects - Avoid outdated lead lists ## Important Note About Pre-Warmed Mailboxes Pre-warmed mailboxes complete the initial warm-up process, but inbox placement can still be affected by: - Email copy - Links - Sending behavior - Lead quality - Recipient spam filters If warm-up emails land in inbox but campaign emails go to spam, the issue is usually related to campaign content or targeting rather than mailbox infrastructure itself. ## Key Takeaways Spam placement is rarely caused by a single issue. Deliverability depends on the combination of: - Healthy infrastructure - Proper warm-up - Good sending behavior - High-quality lead lists - Human-sounding email copy The best approach is to test incrementally and optimize one variable at a time. Small improvements in copy, targeting, and sending habits can significantly improve inbox placement over time.