Guide

Why are my business emails going to spam?

Quotes and invoices that never arrive cost real money. These are the usual causes, in the order worth checking, with what to do about each one.

By Hamza Rivera, updated 8 November 2026

Short answer: Most business email that lands in spam has one of three problems. A sending tool is not covered by your SPF and DKIM records, the records themselves are broken, or the domain has a reputation problem from list quality or complaints. Check the message headers first and fix the record that fails.

The short version

Most business email that lands in spam has one of three problems. A sending tool is not covered by your SPF and DKIM records, the records themselves are broken, or the domain has a reputation problem from list quality or complaints. Check the message headers first and fix the failing record.

The usual causes

SPF, DKIM or DMARC is missing or broken

These three records tell the receiving server which services may send as your domain and whether a message was changed on the way. Gmail requires SPF or DKIM from every sender, and requires SPF, DKIM and DMARC from anyone sending more than 5,000 messages a day to personal Gmail accounts. Yahoo asks for SPF, DKIM and a DMARC record. Without them you are asking to be judged on guesswork. Our plain English guide to SPF, DKIM and DMARC shows what each one does.

A service sends as you and was never added

Your website form, your invoicing tool, your CRM, your newsletter tool and your booking system all send mail that says it comes from your domain. Each one has to be listed in your records or signed with your key. The one nobody remembered is usually the one that lands in spam.

SPF is over the lookup limit

The SPF standard allows 10 DNS lookups while a record is evaluated, and every include counts. A business that has added five tools over the years can pass 10 without noticing. When that happens the receiver gets a permanent error instead of a pass.

Two SPF records instead of one

A domain must have a single SPF record. A second one, often added by a well meaning tool setup guide, makes the result a permanent error under the standard.

The From address does not line up with the authenticated domain

DMARC passes only when the domain that passed SPF or DKIM matches the domain in the From line. Mail sent through a third party under its own domain fails that match even if the third party passes its own checks.

The domain or the sending address is on a blocklist

Blocklists are public lists of addresses and domains linked to spam. Some mail providers consult them. A listing can come from a hacked contact form, an infected computer or a mailing list with bad addresses. We check the major ones in the free domain check.

Sending habits changed suddenly

A quiet domain that suddenly sends hundreds of messages looks like a hijacked account. So does a long list bought or scraped, with many addresses that no longer exist. Both lead to bounces and complaints, which are what providers watch.

People mark your mail as spam

Google asks senders to keep the spam rate shown in Postmaster Tools under 0.10% and to never reach 0.30%. Yahoo asks for under 0.3%. Mail people did not expect, or cannot easily stop, gets reported. An easy unsubscribe link costs less than a complaint.

Outlook and Microsoft mail

Microsoft has its own requirements for domains sending more than 5,000 messages a day to Outlook.com addresses. From 5 May 2025 non-compliant mail from such domains is routed to the Junk folder, with rejection planned later. Small senders are not covered by those numbers, but clean authentication helps everywhere.

What to do, in order

1

Look at the headers of a message that went to spam

In Gmail, open the message and choose Show original. It lists SPF, DKIM and DMARC as PASS or FAIL. That tells you which record to look at first.
2

List everything that sends as your domain

Write down every tool that sends mail with your address in the From line. Ask your web developer about the contact form.
3

Fix SPF and DKIM first

One SPF record covering the sending services, and DKIM switched on in each service with the key published in your DNS.
4

Publish DMARC with a policy that only reports

A DMARC record with p=none and a reporting address lets you see who sends as you before you ask anyone to reject anything. Move to a stricter policy later, in steps.
5

Set up Google Postmaster Tools

Add and verify the domain to see spam rate and authentication results for mail sent to Gmail. It shows nothing until enough mail goes to Gmail each day.
6

Check blocklists and sending habits

Look up the domain on the major public blocklists, clean the list you send to and add an unsubscribe link to anything that is marketing.

Where to read next

These rules were checked against what Google, Yahoo and Microsoft publish on 8 November 2026. Providers change them, so check again if you read this much later.

Questions about emails going to spam

Why are my emails going to spam when I did nothing wrong?

Mail providers judge a message on authentication, reputation and how recipients treat your mail, not on your intent. A tool that sends as your domain without being listed in your records is enough to cause it.

Why do my emails go to spam in Gmail only?

Gmail publishes strict sender rules and acts on them. Check the Show original view of a message sent to Gmail, and set up Postmaster Tools for your domain to see spam rate and authentication results.

Why do my emails go to spam in Outlook?

Outlook has requirements for high volume senders and its own reputation checks. For small senders the usual cause is the same: missing or misaligned SPF, DKIM or DMARC.

How do I check whether my domain is blacklisted?

Look the domain and sending address up on the main public blocklists. Be wary of tools that show one scary result from a list few providers use. Our free domain check covers the major ones and explains what a listing means.

Can you guarantee my emails will reach the inbox?

No. Mailbox providers decide for each message. A correct setup removes the common causes and our before and after test sends show what changed.

Will you do it for me?

Yes. Passieon is an independent agency, not connected to Google, Yahoo or Microsoft. Send your domain through the form on this page for a free written check.