Why your emails go to spam: 9 causes and fixes

1. Your SPF record is missing or broken

SPF is a DNS record that lists the servers allowed to send email for your domain. Without it, a mail provider cannot tell your mail from a forgery. It also breaks in a few common ways: two SPF records on one domain, more than 10 DNS lookups, or a service you send through that is not listed.

Check it in a minute

Type your domain into the SPF checker. It shows your record and whether there is one record only and it ends safely.

Fix it

1. Keep one SPF record per domain. If you find two, merge them into one.
2. List every service that sends for you: your mailbox provider and any sending tool.
3. End the record with ~all.
4. Stay within 10 DNS lookups in total. Each include: counts, and so do the lookups inside it.

The SPF record generator builds the record for you, and SPF for Google Workspace walks through the most common setup.

2. DKIM is not signing your mail

DKIM adds a signature to every message that proves it really came from your domain and was not changed on the way. Your email provider creates the key and you publish it in DNS. If that step was skipped, your mail goes out unsigned.

Check it in a minute

The DKIM checker looks for your key under the names most providers use. If it says it could not check, your provider may use another name; its DKIM settings will say whether the key is published.

Fix it

1. In your mailbox provider’s admin settings, find the DKIM (email authentication) page.
2. Copy the record it gives you into your DNS as a TXT record, at the host name it shows.
3. Many providers also need you to switch signing on once the record is live, so check for a button that says so.

3. There is no DMARC, or it does not align

DMARC tells receiving servers what to do with a message that fails SPF and DKIM. It also checks that the domain in your From address matches the domain SPF or DKIM verified, which is called alignment. Gmail and Yahoo ask bulk senders to have it, and a domain without one looks less trustworthy to every provider.

Check it in a minute

Run the DMARC checker. It shows whether a record exists and which policy it sets.

Fix it

1. Start with p=none. It only reports and never blocks your mail.
2. Add an address for the reports if you want to see who sends as your domain.
3. Once SPF or DKIM passes for every service that sends for you, move to quarantine, then reject.

The DMARC record generator explains each setting as you pick it.

4. A new domain or mailbox that has not been warmed up

A new domain or mailbox has no history, so mail providers have nothing to trust. Sending a lot from day one looks exactly like what spammers do. Warm-up builds a history by starting small and growing slowly.

Check it in a minute

Is the domain or the mailbox less than a few weeks old, or did you just move to it? If so, treat it as new.

Fix it

1. Start with a handful of emails a day, to people likely to read them.
2. Add a little more each day, rather than a big step at once.
3. Hold your campaigns until it has been running for about two weeks.

SendPath’s warm-up starts at 3 emails a day and adds 2 more each day, and a mailbox counts as ready after about two weeks, once its warm-up mail reliably reaches the inbox. See Warm-up in the docs.

5. Sending too much, too fast

Even a warmed mailbox gets flagged when its volume jumps. Providers watch for sudden changes, and one mailbox sending hundreds of emails a day looks very different from several mailboxes each sending a few dozen.

Check it in a minute

Compare what each mailbox sent today with what it sent last week. A sudden jump is the signal.

Fix it

1. Set a daily cap on every mailbox, and keep it modest.
2. Spread your volume over more mailboxes, and over more than one domain if you send a lot.
3. Raise the volume in small steps.

In SendPath, plan on about 30 campaign emails a day per mailbox and 2 to 3 mailboxes per domain. The docs page Choosing a sending domain explains why.

6. A list with invalid or old addresses

An address that does not exist bounces, and every bounce tells providers you are sending to a list you did not build carefully. Old lists are worse: addresses are recycled over time, and some of them become spam traps.

Check it in a minute

Type an address into the email verifier. It checks the format, the kind of address and whether the domain takes mail. It does not ask the mailbox itself; checking that a mailbox really exists is part of the free trial.

Fix it

1. Verify your list before you send to it.
2. Remove shared role addresses such as info@ and anything that has bounced.
3. Do not send again to a list that bounced heavily. Clean it and verify it first.

7. Content that looks like spam

Spam filters read the message. Hype words, too many links, link shorteners, a subject in capitals or with a fake reply marker, and image-only emails all count against you, and a misleading subject line does the most damage with readers.

Check it in a minute

The spam word checker highlights the words filters dislike. The outreach email checker scores the whole message: the unsubscribe link, links, length and tone.

Fix it

1. Write as you would to one person, in plain sentences.
2. Use one link, or none, in a first email, and no short links.
3. Keep capitals, exclamation marks and emoji out of the subject, and never fake a “Re:”.
4. Send real text with light formatting, not one big image.

8. Your domain or IP address is on a blocklist

A blocklist is a public list of domains and IP addresses that mail providers have seen sending spam. Being listed can send a large share of your mail to spam at once, whatever the individual messages say.

Check it in a minute

Look up your sending domain in a public blocklist lookup. If you send through your own server or a sending service, look up its IP address too.

Fix it

1. Stop sending until you know why.
2. Find the cause. It is usually a bad list or a spike in complaints.
3. Fix the cause, then follow that list’s own process to ask for removal.

9. No easy way to unsubscribe, so people report spam

When people cannot unsubscribe easily, they press Report spam instead, and complaints weigh heavily with mail providers. An unsubscribe link is the cheapest way to keep a complaint from happening.

Check it in a minute

Open your last email as a recipient would. Is there a clear unsubscribe link, your postal address and a From name that says who you are?

Fix it

1. Put a working unsubscribe link in every email.
2. Add your postal address. US law (CAN-SPAM) asks for one in commercial email.
3. Use an honest From name and an honest subject.
4. Suppress anyone who opts out straight away, and never add them back.

Gmail and Yahoo show a one-click unsubscribe button when an email carries the right headers, and SendPath adds those headers to every email it sends.