Why Do My Emails Go to Spam?
Why do your emails go to spam? SPF, DKIM and DMARC, sender reputation, blacklists, content, the Gmail and Yahoo sender rules and tools to test your email.
The most common reason your emails go to spam is that the recipient's email provider can't be sure the email really came from you. Gmail, Outlook and other providers score every email based on authentication records, the sender's reputation, the content and recipients' past behavior. The good news is that most problems are solved with a few DNS records and the right sending habits.
This article walks you step by step through why emails end up in spam, how to test for it and what you need to do to improve deliverability.
1. Missing authentication: SPF, DKIM and DMARC
These three records prove that your email was sent from a server authorized on behalf of your domain and wasn't altered on the way:
- SPF: Lists the servers that can send email on behalf of your domain.
- DKIM: Adds a digital signature to the email; the recipient verifies the signature with the public key in your domain's DNS.
- DMARC: Decides what happens when the SPF and DKIM checks fail, and has reports sent to you.
If one of the records is missing or wrong, your emails go to spam or aren't delivered at all. The most common mistake is not updating the SPF record when a new service that sends email (for example a newsletter tool or your website's form plugin) is added. We walk through setting up the records step by step in our SPF, DKIM and DMARC article.
2. Sender reputation and blacklists
Providers look at the history of the IP address and the domain sending the email:
- Blacklists: If your IP address or domain has landed on a blacklist (for example the Spamhaus lists), many providers reject your emails. A compromised email account or spam sent through a website form are the most common causes.
- New domains: New domains and IP addresses with no sending history are filtered more strictly at first.
- Reverse DNS (PTR): If the IP address sending the email has no reverse DNS record, or it doesn't match the domain, emails can be rejected. If you run your own mail server, you need the provider that owns the IP address to set this record; the details are in our Your own mail server or email hosting? article.
3. Recipient behavior
Filters also learn how recipients react to your emails:
- If your emails are often marked as spam, your next emails go to spam too.
- Emails nobody opens, or that go to addresses that don't exist, lower your reputation.
- Recipients adding you to their address book and replying to your emails raises your reputation.
That's why not sending to people who aren't expecting email from you and keeping your lists clean is as important as the technical settings.
4. Content
Content alone is rarely decisive, but its effect grows when combined with other problems:
- Emails made up of a single image with very little text.
- Shortened links, a large number of links or links to blacklisted domains.
- A sender name that doesn't match the email address, or misleading subject lines.
- Broken HTML and emails without a plain-text version.
Gmail and Yahoo sender rules
Since 2024, Gmail and Yahoo have expected senders to meet certain requirements. For all senders, SPF or DKIM, a valid reverse DNS record and a TLS connection are expected. For bulk senders sending more than roughly 5,000 emails a day to Gmail, additionally:
- All three of the SPF, DKIM and DMARC records must be in place.
- The domain in the From address must align with the domain authenticated by SPF or DKIM.
- Marketing emails must support one-click unsubscribe.
- The spam complaint rate must be kept low.
Emails from bulk senders who don't follow these rules can be rejected or sent to spam.
Testing tools
- mail-tester.com: You send an email to the address it gives you; the tool checks your authentication records, blacklists and content and gives you a score.
- Google Postmaster Tools: Shows your domain's reputation, spam rate and authentication results in Gmail.
- MXToolbox: Checks your DNS records and whether your IP address is on blacklists.
- Email headers: The
Authentication-Resultsline in the raw headers of a received email shows the SPF, DKIM and DMARC results directly.
Checklist for improving deliverability
- Set up SPF, DKIM and DMARC records and add every service that sends email to SPF.
- Send your website's forms through authenticated SMTP instead of PHP's
mail()function. - Send your business correspondence and your bulk newsletters from different accounts or services.
- Send only to people who have given permission, make unsubscribing easy and remove invalid addresses.
- If you're starting with a new domain, increase your sending volume over time.
- Protect your accounts with strong passwords and two-factor authentication; a single compromised account can lower the reputation of your entire domain.
- Test regularly; when something goes wrong, mail-tester and Postmaster Tools are the first tools to warn you.
We cover your email clients' settings in our IMAP vs POP3 article.
Nodesty email hosting
Nodesty email hosting plans offer email addresses on your own domain, webmail and IMAP/POP3 access; incoming email is filtered with SpamExperts, so spam and malicious emails are stopped before they reach your inbox. During setup, you add the domain verification and DKIM details from your panel to your DNS so that the emails you send are authenticated. If you use web hosting for your website, sending your forms over SMTP through your email hosting account reduces the chance of form emails ending up in spam.
Frequently Asked Questions
My emails only go to spam in Gmail. Why?
Every email provider uses its own filters and reputation scores. Gmail puts a lot of weight on authentication records, on how recipients interact with your emails and on spam complaints. With Google Postmaster Tools, you can track your domain's reputation and authentication results in Gmail.
Do I need all three of SPF, DKIM and DMARC?
For deliverability, we recommend using all three together. SPF states which servers can send on behalf of your domain, and DKIM proves the email hasn't been altered; DMARC decides what happens based on the results of these two checks. Major providers expect bulk senders to have all three.
My domain is on a blacklist. What should I do?
First find the cause and fix it; it could be a compromised account, spam sent through a website form or a list collected without permission. Once the problem is fixed, request removal on the website of the organization that runs the blacklist. Requests made before the cause is gone usually go nowhere.
Why do emails I send from a new domain go to spam?
New domains and IP addresses have no sending history, and filters treat such senders with suspicion at first. Set up your authentication records completely, send a small number of emails that recipients really expect in the first weeks and increase your sending volume over time.
My newsletter emails go to spam. What should I do?
Send only to people who have given permission, add an easy unsubscribe link to every email and regularly remove unresponsive addresses from your list. Using a bulk email service for mass mailings instead of your business email account also protects the reputation of your everyday correspondence.
I get a lot of spam in my inbox. What can I do?
The most effective way to reduce incoming spam is to use a service that filters emails before they reach your inbox. Not publishing your email address as plain text on websites and not clicking links in suspicious emails also reduces both spam and the risk of phishing.
About the author
Nodesty Team · Infrastructure & Support
The Nodesty team runs our servers, network and DDoS protection day to day and answers customer support requests around the clock. These guides come from that work.
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