Why Your Store's Emails Go to Spam, and How to Fix It

Your store's marketing email lands in spam when Gmail and Yahoo can't verify it's really from you, or when too many people mark it as spam. Check authentication (SPF, DKIM, DMARC) first, then your spam complaint rate, then who you're sending to. Hayes Media, an eCommerce growth agency that runs email and SMS retention for Shopify and DTC brands, wrote this checklist from the rules Gmail and Yahoo publish for senders.

This page covers the spam folder only. If your email reaches Gmail but sits under Promotions, that's a different question, and our guide to the Gmail Promotions tab answers it. If your messages come back as bounces instead, hard bounce vs soft bounce explains what each type means and when to suppress.

Why are my emails going to spam?

Inbox providers decide where your email goes based on signals they can measure, starting with whether the message provably comes from your domain and how the people receiving it react. Gmail's sender guidelines say unauthenticated messages "might be marked as spam or rejected with a 5.7.26 error", and that "Over time, user spam reports can lower your domain’s reputation."

For a Shopify brand sending from Klaviyo or a similar platform, the causes fall into six checks:

Authentication. SPF, DKIM and DMARC aren't set up for your own domain, or they don't line up with the address in your From: line.

Complaints. Too many people report your campaigns as spam.

Engagement. You keep mailing profiles who stopped opening or clicking a long time ago.

List source. Some addresses on your list never asked to hear from you.

Volume. Your send size or frequency jumped suddenly, for example for a sale.

The message itself. The sender name, the content or the unsubscribe setup looks misleading.

What do Gmail and Yahoo require from bulk senders?

Both providers publish their rules. Google's FAQ defines a bulk sender as "any email sender that sends close to 5,000 messages or more to personal Gmail accounts within a 24-hour period." It adds: "Senders who meet the above criteria at least once are permanently considered bulk senders." One big campaign can put a growing store over that line for good.

Gmail's guidelines list these requirements for senders of more than 5,000 messages a day, quoted from its page:

Authentication: "Set up SPF and DKIM email authentication for your domain." Also: "Set up DMARC email authentication for your sending domain. Your DMARC enforcement policy can be set to none."

Alignment: "For direct email, the domain in the sender's From: header must be aligned with either the SPF domain or the DKIM domain."

Spam rate: "Keep spam rates reported in Postmaster Tools below 0.30%."

Unsubscribe: "Marketing messages and subscribed messages must support one-click unsubscribe, and include a clearly visible unsubscribe link in the message body."

Yahoo's Sender Hub lists the same core rules for bulk senders: "Implement both SPF & DKIM", "Publish a valid DMARC policy with at least p=none", "Honor unsubscribes within 2 days" and "Keep your spam rate below 0.3%".

Google also sets a lower line. Its guidelines say: "Keep spam rates reported in Postmaster Tools below 0.10% and avoid ever reaching a spam rate of 0.30% or higher." Its FAQ goes further: "Even today, user-reported spam rates greater than 0.1% have a negative impact on email inbox delivery for bulk senders." So 0.3% is the ceiling, and 0.1% is where Google says inbox delivery already starts to suffer.

Is your domain set up with SPF, DKIM and DMARC?

SPF lists the servers allowed to send email for your domain. Google: "The SPF record for your domain should include all email senders for your domain."

DKIM adds a signature to each message. Google: "Receiving servers use DKIM to verify that the domain owner actually sent the message."

DMARC sets the rule for mail that fails. Google: "DMARC tells receiving servers what to do with your messages that don’t pass SPF or DKIM."

Alignment is where a setup that looks right can still fail. If your email platform signs messages with its own shared domain instead of yours, your From: address says yourbrand.com but the signature points somewhere else. That fails the alignment rule both Gmail and Yahoo list. The fix is to set up your own sending domain in your platform's settings, publish the DNS records it gives you at your domain provider, and add a DMARC record. Google's advice for anyone using a provider is short: "If you use an email service provider, verify that they authenticate your domain’s email with SPF and DKIM."

Every tool that sends as your domain needs to be covered, including your helpdesk, your review app and any other app that emails customers from your address. Google warns: "If your third-party senders aren't included in your SPF record, messages from these senders are more likely to be marked as spam." To confirm it's working, Google lists "If messages are authenticated" among the things Postmaster Tools shows you about mail you send to Gmail users.

What's your spam complaint rate?

If authentication passes and you're still in spam, complaints are the next suspect. Gmail is plain about it: "If messages from your domain are frequently reported as spam, future messages from you are more likely to be marked as spam."

Google's number comes from Postmaster Tools, and its FAQ says "Spam rate is calculated daily." Yahoo notes that its spam rate "is calculated in our system based on mail delivered to the inbox". So the complaint rate in your email platform won't match either provider's figure exactly. Treat your platform's number as an early warning, and Postmaster Tools as the number Gmail's thresholds refer to.

Don't use open rate as your spam check. Google says "Google doesn't track open rates" and "Low open rates aren't necessarily an accurate indicator of deliverability or spam classification issues." Our piece on email open rate benchmarks for eCommerce covers how far you can still trust that number.

Are you still emailing people who stopped engaging?

Yahoo puts it directly: "Sending email to users who are not reading them, or who report them as spam, will harm your delivery metrics and reputation." Google's subscription guidance says: "Consider unsubscribing recipients who don’t open or read your messages."

The mechanism is simple. Someone who forgot they signed up has no reason to look for your unsubscribe link, and the spam button is right there.

In practice, that means sending campaigns to an engaged segment by default: profiles who opened, clicked or ordered within a window that fits your own buying cycle. Mail the wider list only on purpose, and give lapsed profiles one clear chance to stay. Yahoo suggests: "Consider sending a reconfirmation email to inactive subscribers periodically." Cleaning dead and risky addresses off your list is its own job, worth doing once this checklist is done. Repeat bounces are a separate signal, and Google's advice is to "Automatically unsubscribe recipients who have multiple bounced messages."

Where did your subscribers come from?

Every address should belong to someone who asked to hear from you. Both providers say so. Google: "Don't purchase email addresses from other companies." Yahoo: "Don't purchase mailing lists or subscribe users by having an opt-in checkbox automatically checked on your website."

Beyond bought lists, watch for quieter sources: a giveaway partner's entrant file, a wholesale or event list imported into your marketing list, a signup box that's ticked by default, or old customers moved over from a previous platform who never agreed to marketing.

For new signups, Yahoo recommends confirmed opt-in: "When users subscribe to your mailing list, send them an email asking them to click to confirm their opt-in."

Did your sending volume jump suddenly?

Gmail also looks at how fast your volume changes. Its guidelines say: "Avoid introducing sudden volume spikes if you do not have a history of sending large volumes. For example, immediately doubling previously sent volumes suddenly could result in rate limiting or reputation drops."

This is how a sale can trip that rule. Take a brand (made-up numbers) that mails 20,000 engaged profiles once a week, then sends daily to its full list of 60,000 for a sale week. Volume, audience and frequency all changed at once. Yahoo makes the frequency point too: "Don't start sending daily emails to subscribers of your weekly or monthly mailing." For sale planning, our Black Friday email strategy covers what to send before, during and after.

A new sending domain or dedicated IP needs warming, which means raising its volume gradually instead of all at once.

Does the email itself look honest?

Sender name. Google: "Sender display names should be used exclusively to identify the sender." It lists "Last Chance" as an example of a display name not to use.

Subject lines. Google asks senders not to use subject lines "starting with Re: or Fwd: unless the messages are actual replies or forwards".

Hidden content. Google: "Hiding content might cause messages to be marked as spam."

Mixed messages. Google: "Don't mix different types of content in the same message. For example, don't include promotions in sales receipt messages." Here's where the line sits between transactional and marketing email for your store.

Unsubscribe. Put a visible unsubscribe link in every marketing email and make sure one-click unsubscribe is switched on. If someone can't find the way out, the spam button is the one they'll use.

What does this look like in numbers?

These numbers are made up to show the mechanism. A skincare brand has 60,000 profiles. 18,000 of them opened, clicked or ordered recently. The other 42,000 haven't engaged in a long time.

Send A, engaged segment only. 18,000 emails and 9 spam complaints. 9 divided by 18,000 is 0.05%.

Send B, full list. 60,000 emails and 90 complaints: the same 9 from the engaged group, plus 81 from the unengaged 42,000. 90 divided by 60,000 is 0.15%.

Send B reaches more inboxes, but its rate sits above the 0.10% Google asks senders to stay under, even though it's below the 0.30% ceiling. In this made-up case, repeating Send B every week keeps adding complaints against your domain, and Google says messages from a domain that's frequently reported are "more likely to be marked as spam". That can include the mail your 18,000 engaged people get, because the reputation belongs to your domain, and every send from that domain shares it.

When does this checklist not apply?

Your emails bounce. A bounce means the message was refused or couldn't be delivered, so start with the bounce codes instead.

Only one inbox shows you in spam. One person's filter may be the reason. Google notes that "Recipients can mark valid messages as not spam, so future messages from the sender should be delivered to their inbox."

Your domain is flagged as unsafe. Google says to "Check regularly that your domain isn’t listed as unsafe with Google Safe Browsing." That points to a problem with your website, so fix the site first.

You send fewer than 5,000 a day to Gmail. The bulk rules don't all apply, but the all-senders list still does, including "Set up SPF or DKIM email authentication for your sending domains" and "Keep spam rates reported in Postmaster Tools below 0.3%."

You're on a shared IP. Google: "The activity of any senders using a shared IP address affects the reputation of all senders for that shared IP address." That's your platform's job to manage, so raise it with their support.

Who can fix this for your store?

You can work through this list yourself. If you'd rather have it done, Hayes Media runs retention for eCommerce brands across email, SMS, loyalty programs and subscribe-and-save. Its retention site (email.hayesmedia.co) reports "8 yrs" of retention expertise, "$500M+" in client revenue driven, and that it's "Trusted by 50+ eCom brands". Those figures and Hayes's case studies are published by Hayes on its own sites, and Hayes has no third-party review profile or Klaviyo partner listing, so weigh them with that in mind.

We work in Klaviyo for most accounts and have experience in most other email and SMS platforms. Email on its own is a complete engagement. See what our email and SMS service covers, or read our email marketing audit.

Hayes Media works with brands doing at least $100K per month in revenue. That's a guideline, not a gate: a smaller brand with a clear budget set aside to scale and real order volume can still be a fit. One-time email projects start from $2,000 USD, and retainers for ongoing full management start from $4,000 USD per month, scoped on the discovery call.

If your campaigns are landing in spam, a discovery call gets you an audit of your deliverability and sending setup: authentication, complaint rate, segments and sending pattern, and what to fix first. No onboarding fees. No lock-in contracts. No junior marketers. Book a discovery call

Sources

Google, Email sender guidelines: https://support.google.com/a/answer/81126

Google, Email sender guidelines FAQ: https://support.google.com/a/answer/14229414

Yahoo Sender Hub, Sender Requirements and Recommendations: https://senders.yahooinc.com/best-practices/