Why Are My Emails Going to Spam? 15 Causes and How to Fix Each One

Just because an email was sent successfully does not mean it will reach the inbox. It may be delivered but automatically routed to the spam folder because of authentication problems, sender reputation, your recipient list, or the way you send emails. The cause may also lie in the content of the message itself or in the recipient's filtering rules.

Most of these problems can be identified and fixed. In this guide, we'll look at 15 of the most common reasons emails land in spam, how to determine which one is affecting your messages, and what you can do to improve their deliverability.

1. Your SPF Record Is Missing or Misconfigured

SPF (Sender Policy Framework) defines which servers and services are authorized to send messages on behalf of your domain. If the record is missing, includes the wrong services, has multiple SPF records, or exceeds the 10-DNS-lookup limit, SPF authentication may fail. This can hurt email deliverability, especially when you use several third-party services to send messages.

How to fix it:

• Make a list of every service that sends messages from your domain.
• Keep only one SPF record for the domain.
• Add all legitimate sending services to that record.
• Check for errors related to the DNS lookup limit.
• Test the record after making changes.

2. DKIM Is Missing, Misconfigured, or Failing

DKIM (DomainKeys Identified Mail) adds a digital signature to outgoing messages, allowing receiving servers to verify that the message was authorized by the signing domain and was not altered in transit. A missing key, incorrect DNS record, invalid selector, or signature problem can cause DKIM authentication to fail.

How to fix it:

• Enable DKIM with your email provider or sending platform.
• Publish the correct DKIM public key in DNS.
• Confirm that the selector matches the one used by your provider.
• Check the authentication results of a received message and make sure DKIM shows dkim=pass.

3. DMARC Is Missing or Misconfigured

DMARC (Domain-based Message Authentication, Reporting, and Conformance) specifies what policy the domain owner prefers to be applied to messages that fail DMARC verification. DMARC also checks whether the domain authenticated through SPF or DKIM matches the domain shown in the From field.

A missing, malformed, or poorly configured DMARC record can reduce a domain's protection against spoofing (forging the sender address to make a message appear to be sent from a legitimate domain).

How to fix it:

• Publish a valid DMARC record for your sending domain.
• When first implementing DMARC, start with a monitoring policy such as p=none.
• Review authentication reports before applying a stricter policy.
• Make sure your legitimate sending services pass authentication and alignment checks.

4. SPF or DKIM Passes, but DMARC Alignment Fails

Passing SPF or DKIM does not necessarily mean the message will also pass DMARC. DMARC checks whether the authenticated domain aligns with the domain the recipient sees in the From field. Problems can occur when a third-party platform sends messages on your behalf using a different domain without proper alignment.

How to fix it:

• Check the SPF and DKIM domains in the message headers.
• Compare them with the domain in the From field.
• Configure a custom return-path or envelope-from domain if your provider supports it.
• Where possible, configure DKIM so that messages are signed with your domain.
• Test messages from every platform that sends email on your behalf.

5. Your Sending Server Does Not Have Proper DNS Identity

Mail servers need a valid identity that receiving providers can verify. With self-hosted or dedicated sending infrastructure, a missing or incorrect reverse DNS (PTR) record, a mismatch with forward DNS, or an invalid hostname can make the server appear less trustworthy to receiving systems. Google, for example, requires valid forward and reverse DNS records for senders delivering messages to Gmail.

How to fix it:

• Set a valid PTR record for the IP address you send from.
• Make sure the hostname resolves back to the same IP address through forward DNS.
• Use a consistent hostname in your mail server configuration.
• Make sure connections use TLS.
• Recheck the DNS configuration after making changes.

6. Your Domain or IP Address Has a Poor Reputation

Email providers track the history and reputation of the domains and IP addresses used to send messages. High spam complaint rates, frequent delivery failures, and unwanted messages can gradually damage that reputation. As a result, future emails are more likely to be filtered as spam, even when SPF, DKIM, and DMARC are configured correctly.

How to fix it:

• Check your domain and IP reputation using appropriate monitoring tools.
• Identify when the decline began and whether it coincided with a specific change.
• Review campaigns, recipient lists, and infrastructure changes from that period.
• Reduce sending to inactive or problematic addresses and focus on recipients who actually expect your messages.
• Send emails only to users who have consented to receive them and maintain consistent good sending practices.

7. Too Many Recipients Are Marking Your Emails as Spam

Spam complaints are a strong signal that recipients do not want your messages. Even a relatively low complaint rate can affect future deliverability, especially when complaints occur across several consecutive campaigns. Google recommends keeping the reported spam rate below 0.10% and avoiding rates of 0.30% or higher.

How to fix it:

• Reduce or stop sending to recipients who have not opened or interacted with your emails for a long time.
• Clearly remind recipients why they are receiving your messages, especially if they subscribed a long time ago.
• Use clear, non-misleading subject lines and an easily recognizable sender name.
• Provide an easy-to-find unsubscribe option for marketing emails.
• Monitor spam complaint rates regularly and take action at the first signs of deterioration.

8. Your List Contains Invalid or Inactive Email Addresses

Old or poorly maintained lists often contain invalid addresses and subscribers who have not interacted with your messages for a long time. Repeated delivery attempts to these addresses increase bounce rates and can damage your sender reputation.

How to fix it:

• Promptly remove addresses where emails consistently cannot be delivered (hard bounces).
• Validate addresses collected through signup forms and other sources.
• Monitor subscribers who have not opened or interacted with your emails for an extended period.
• Periodically clean your list of invalid and long-term inactive addresses.
• Keep your list up to date and focus your sending on people who still show interest in your messages.

9. You Use Purchased Lists or Lists Containing Spam Traps

Purchased or automatically collected lists contain addresses belonging to people who have not consented to receive your messages. They may also contain spam traps, which are special email addresses used to identify senders distributing unwanted email or using questionable methods to collect contacts. Sending to these addresses can generate more spam complaints and damage the reputation of your domain or IP address.

How to fix it:

• Do not use purchased, automatically collected, or scraped lists of email addresses.
• Build your own list through signups where users clearly consent to receive your messages.
• Tell subscribers what type of content they will receive and how often you will email them.
• Check the source and quality of addresses before adding them to your sending platform.
• Keep records of when, where, and how each subscriber gave consent.

10. You Increased Your Sending Volume Too Quickly

Suddenly sending significantly more emails than usual can be a risk signal for email providers. This is particularly important for new domains and IP addresses that do not yet have an established sending history. Similar problems can occur when launching a large campaign, adding many new recipients, or resuming email activity after a long period of inactivity.

How to fix it:

• Increase sending volume gradually, especially when using a new domain, IP address, or sending service.
• After a long period of inactivity, do not immediately resume with large campaigns.
• Start with your most active recipients, who regularly open or interact with your emails.
• Avoid sharp fluctuations and maintain a reasonably consistent sending pattern.

11. You Made a Significant Change to How You Send Email

Changing your email platform, sending IP address, or sending domain can temporarily affect deliverability. Even if the new configuration is technically correct, email providers may not yet have enough data to evaluate the reputation and behavior of the new sender. The risk is greater if the change is immediately followed by a large volume of email.

How to fix it:

• Plan the move to a new platform, IP address, or sending domain in advance.
• Configure and test SPF, DKIM, and DMARC before sending at scale.
• Where possible, transition to the new infrastructure gradually rather than moving all traffic at once.
• Monitor deliverability, the percentage of emails that cannot be delivered (bounce rate), and spam complaints during the transition.
• If deliverability declines, check whether the problem coincides with a specific change in your infrastructure or sending practices.

12. Your Shared IP Address Has a Poor Reputation

With some email services, multiple senders use the same IP address. This means its reputation depends not only on your own practices but also on the behavior of other users. If they send spam, generate large numbers of complaints, or violate provider policies, the reputation of the shared IP can deteriorate and affect the deliverability of your emails as well.

How to fix it:

• Check the reputation of the IP address used to send your emails.
• Ask your provider how it monitors the reputation of shared IP addresses and responds to abuse by other users.
• If deliverability problems persist, investigate whether the reputation of the shared IP is contributing to the issue.
• If you have a sufficiently large and consistent sending volume, consider using a dedicated IP address.
• Do not move to another IP address before identifying the cause of the poor reputation. If your own sending practices are responsible, changing IPs will provide only a temporary fix.

13. Your Email Content or Formatting Looks Suspicious

Email providers analyze not only sender reputation and authentication but also the content and structure of the email itself. Misleading subject lines, hidden content, poorly structured HTML, or overly aggressive promotional elements can increase the likelihood of a message being filtered as spam. However, this does not mean that individual words such as “free” or “offer” automatically send an email to the spam folder.

How to fix it:

• Use a clear, non-misleading subject line and an easily recognizable sender name.
• Avoid hidden content and elements that could mislead recipients about the sender or purpose of the message.
• Use clean, properly structured HTML that displays correctly across different devices and email clients.
• Make the purpose of the message and the reason the recipient is receiving it clear from the beginning.
• If certain templates land in spam more often, compare their content and formatting with emails that consistently reach the inbox.

14. Your Links or Tracking Domains Have a Poor Reputation

Email providers check not only the sender's reputation but also the domains and links included in a message. Links to compromised, suspicious, or untrustworthy websites can increase the likelihood of an email being filtered as spam. Tracking domains with a poor reputation can cause similar problems, as can multiple redirects that make the final destination harder to identify.

How to fix it:

• Check the domains and final landing pages your email links point to.
• Avoid unnecessary URL shortening services and excessive redirects.
• Use a reputable click-tracking service and, where possible, your own tracking domain.
• Make sure the websites you direct recipients to use HTTPS, have not been compromised, and are functioning properly.
• If a domain or page has been compromised or flagged as suspicious, remove the link from your emails until the issue has been resolved.

15. The Problem Is With the Recipient's Filters

The sender is not always responsible when an email lands in spam. If your emails reach most recipients normally but regularly go to spam for one particular person or organization, the problem may be local to that recipient. Possible causes include individual mailbox rules, a blocked address or domain, corporate security filters, or previous spam reports involving your messages.

How to fix it:

• Ask the recipient to check their spam folder and, if they find the message there, mark it as Not Spam.
• Ask them to add your email address to their contacts or safe sender list if their email service provides that option.
• Check whether mailbox rules are automatically moving or blocking your messages.
• If the recipient uses a business email account, their IT administrator can check whether corporate security filters are blocking your address, domain, or messages.
• Check how the same emails are delivered to other recipients. If the problem occurs only with one address or organization, the cause is likely on the recipient's side.

Conclusion

When emails repeatedly land in spam, the solution is to identify and fix the underlying issue rather than make random changes. Authentication, reputation, list quality, sending behavior, message content, and recipient-side filters can all affect inbox placement.

Because authentication depends on DNS records tied to your domain, keeping control of your domain and its settings is an important part of maintaining a reliable sending setup.

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