Check SPF, DKIM and DMARC
Missing or misaligned authentication is one of the most common reasons legitimate mail lands in spam. Make sure every service sending for your domain passes SPF or DKIM with a domain that aligns with your From address, and publish a DMARC record.
Check Your Domain for Email Deliverability
Look up the published SPF, DKIM and DMARC records with the Domain Health report or the individual checkers. A valid record only proves that the configuration exists, not that each sending service uses it. Confirm it by reading the Authentication-Results header of a message that service actually sent.
Email Deliverability and Sender Reputation
Mailbox providers judge your domain and sending IP addresses by past behavior, including spam complaints, bounces and how recipients engage. A clean DNS setup cannot make up for a poor reputation.
Email Delivery Failure Reasons
Bounce messages and SMTP replies often name the cause, such as an unknown user, a full mailbox, a policy block or an authentication failure. Read the full response code and text rather than only the summary line. Remove addresses that hard bounce, because repeated sends to them hurt your reputation.
| Evidence | What it helps diagnose | What it cannot prove |
|---|---|---|
| DNS records | Published configuration | Mailbox existence or reputation |
| Authentication-Results | A receiver’s message evaluation | Every future delivery |
| Bounce responses | A delivery failure reason | Recipient interest |
| Local content scan | Editable message patterns | Inbox placement |
Why Are My Emails Going to Spam All of a Sudden?
A sudden change usually follows a change on your side, such as a new sending service, an edited DNS record, a large list import or a jump in volume. Compare the date the problem started with your recent changes before you test anything else.
Why Do Some Emails Go to Spam and Others Don’t?
Different messages can come from different services, so one may be authenticated and another not. Filters also score each message on its content, links and the recipient’s history with you. Compare the headers of a message that reached the inbox with one that went to spam to find the difference.
How to Stop Emails Going to Spam
Fix authentication first, then send only to people who asked for your mail and make leaving easy. Change one thing at a time and measure the result with real deliveries.
Email Deliverability Best Practices
Use confirmed opt-in where you can, remove addresses that bounce or never engage and keep sending volume steady. Write a specific subject line, use a recognizable sender name and avoid misleading urgency or hidden links. Bulk senders should support one-click unsubscribe and honor requests quickly.
Email Deliverability Test
Send the same message to test mailboxes you control at the major providers and note whether it lands in the inbox or in spam. Open the original source of each copy to read the Authentication-Results header. A content score from a spam checker is only a heuristic and cannot predict inbox placement.
Frequently Asked Questions
Why Do My Emails Go to Spam in Gmail?
Gmail weighs authentication, sender reputation and how its users react to your messages. Its sender guidelines require SPF or DKIM for all senders, and bulk senders also need DMARC, one-click unsubscribe and a low spam complaint rate. Gmail’s Show original view shows how it evaluated your message.
Why Are My Emails Going to Junk Mail?
Junk is Outlook’s name for the spam folder, so the causes are the same: authentication, reputation, recipient behavior and content. Outlook also applies each recipient’s own blocked and safe sender lists. Ask a recipient to mark your message as not junk only after you fix the underlying cause.
Why Are My Business Emails Going to Spam?
Business mail often goes to spam when a new domain has no sending history, when a website or CRM sends without authentication or when the domain has no DMARC record. Check every system that sends on your behalf, not only your mailbox provider. Start a new domain with modest volumes to people who expect your mail.
How Can I Test If My Email Is Going to Spam?
Send a test to mailboxes you own at Gmail, Outlook and Yahoo and check which folder it reaches. Repeat the test after each change so you can see which fix helped. A few test accounts give an indication, not a guarantee for every recipient.