Learn the most common reasons emails land in spam and how to fix them to improve inbox placement, sender reputation, and engagement.
Before you begin
Even if your emails are sent successfully, inbox providers like Gmail or Yahoo ultimately decide where they land—inbox, promotions, or spam.
To understand the foundation, review Email Deliverability Best Practices.
Also, ensure your setup is correct by checking Understanding Email Authentication.
Spam placement is usually not caused by a single issue—it’s a combination of signals that affect your sender reputation.
The biggest reason: Poor sender reputation
Sender reputation is how inbox providers evaluate your trustworthiness as a sender.
If your reputation is low, your emails are far more likely to go to spam.
Learn more in Understanding Sender Reputation.
What affects your sender reputation
Inbox providers evaluate multiple factors:
Engagement (opens, clicks)
Sending frequency and volume
Bounce rates
Spam complaints
Unsubscribe rates
A decline in any of these can push your emails into spam.
1. Low engagement (most common cause)
If users aren’t opening or clicking your emails, inbox providers assume your content is not valuable.
Common issue:
Sending to inactive or “never engaged” users
How to fix:
Segment and target engaged users only
Suppress inactive contacts
Run re-engagement campaigns
This directly impacts your sender reputation and deliverability.
2. High spam complaint rates
When users mark your email as spam, it sends a strong negative signal.
Healthy benchmark:
Keep spam complaints below 0.01%
How to fix:
Set clear expectations during signup
Send relevant, personalized content
Avoid over-emailing
See How to Reduce Spam Complaint Rates for detailed steps.
3. High unsubscribe rates
Unsubscribes are normal—but high rates indicate poor targeting or irrelevant content.
Healthy benchmark:
Keep unsubscribe rates below 0.3%
How to fix:
Improve segmentation
Align content with user expectations
Adjust sending frequency
4. Sending too frequently (or inconsistently)
Sending too many emails in a short time can overwhelm users and trigger spam filtering.
Common mistakes:
Multiple emails per day to the same users
Sudden spikes in volume
How to fix:
Maintain a consistent sending cadence
Segment based on engagement
Avoid overloading inboxes
Learn more in Email Deliverability Best Practices.
5. High bounce rates
Bounce rate reflects failed deliveries—and high rates signal poor list quality.
Healthy benchmark:
Keep bounce rates below 1%
How to fix:
Clean your email lists regularly
Remove invalid or inactive addresses
Avoid purchased lists
6. Issues with your email content
Spam filters analyze your email content for suspicious patterns.
Common triggers:
ALL CAPS subject lines
Excessive punctuation (!!! $$$)
“Spammy” phrases (e.g., “100% FREE”, “Act Now”)
Too many links
Image-heavy emails with little text
Best practices:
Use balanced text + images
Keep content clear and relevant
Include alt text for images
Avoid unnecessary HTML/code
You can also test emails using How to Test Email Content for Spam Triggers.
7. Missing or incorrect authentication
If your emails are not properly authenticated, inbox providers may reject or filter them.
Required protocols:
SPF
DKIM
DMARC
How to fix:
Set up a branded sending domain
Ensure domain alignment
Verify authentication status
Learn more in:
8. Not meeting Gmail & Yahoo requirements
Inbox providers have stricter rules for senders—especially high-volume ones.
Key requirements:
Use a branded sending domain
Set up DMARC authentication
Align your “From” domain with the sending domain
Keep spam complaints low
Include an unsubscribe link
These are now essential for consistent inbox placement.
9. Sending from free email domains
Using addresses like:
@gmail.com
@yahoo.com
As your “From” address can harm deliverability.
Why this is a problem:
Lack of authentication control
Poor trust signals
Fix:
Use your own domain (e.g., hello@yourbusiness.com)
Set up proper sending infrastructure
10. Poor list hygiene
Old, unengaged, or purchased lists are one of the biggest causes of spam placement.
How to fix:
Remove inactive subscribers
Use double opt-in
Regularly clean your lists
Also, review Understanding Spam Traps to avoid hidden risks.
Key takeaway
If your emails are going to spam, it’s almost always due to reputation + engagement + setup issues combined.
To fix it:
Improve engagement
Clean your lists
Fix authentication
Optimize content
Maintain consistent sending