Quick Summary: Three of the most effective ways to keep Mailchimp marketing emails out of spam folders are: sending from a domain-connected email address, authenticating your domain with Mailchimp using DKIM and DMARC records, and routing email through a dedicated SMTP service or email server like Microsoft 365. Together, these steps build the sender reputation that inbox providers trust.

You've crafted the perfect email campaign. The subject line is sharp, the content is compelling, and the send button has been clicked with confidence. Then — silence. Low open rates, no clicks, and a sinking suspicion your emails never made it to anyone's inbox.

Spam filtering is ruthless, and it doesn't care how good your content is. What it does care about is whether you've done the technical groundwork to prove you're a legitimate sender. The good news? That groundwork comes down to three clear steps — and once they're in place, your deliverability improves dramatically.

This post walks you through each one.

Trick 1: Send From an Email Address Tied to Your Domain

The first and most foundational step is deceptively simple: stop sending Mailchimp campaigns from a free email address.

Addresses like yourbusiness@gmail.com or yourbrand@yahoo.com cannot be properly authenticated. As Mailchimp notes in their About Email Domain Authentication article, public email services simply don't support the authentication methods inbox providers now require. That means any campaign sent from a free address is already fighting an uphill battle before it even leaves the server.

The fix is to use an address connected to a domain you own — something like hello@yourbusiness.com. This isn't just a technical requirement; it also signals professionalism and consistency to your subscribers.

If you don't yet have a domain-based email address, check whether your existing hosting package already includes one before purchasing anything new. Many hosting plans come with email addresses bundled in. Explore your email hosting package options to see what's available.

It's also worth knowing that Gmail and Yahoo now require a published DMARC record for bulk senders — specifically, those sending more than 5,000 emails to Gmail or Yahoo addresses within a 24-hour period. If your list is growing, getting this right early saves a great deal of trouble later.

Trick 2: Confirm and Authenticate Your Domain in Mailchimp

Once you have a domain-based email address, the next step is verifying and authenticating it inside Mailchimp. These are two separate processes, and both matter.

Verification is straightforward. Go to Account & Billing > Domains in Mailchimp, add your sending address, and click the confirmation link Mailchimp sends to that inbox. This confirms you have access to the address — but it doesn't improve deliverability on its own.

Authentication is where the real work happens, and it involves adding specific records to your domain's DNS (Domain Name System) settings. Mailchimp's email domain authentication guide covers the full process, and there are two ways to go about it.

What DNS records do you need for Mailchimp authentication?

Mailchimp's authentication setup requires three DNS records in total.

Two CNAME records — for DKIM

DKIM (DomainKeys Identified Mail) uses cryptographic keys to verify that your emails genuinely came from your domain and haven't been altered in transit. Mailchimp configures DKIM via two CNAME (Canonical Name) records — records that link one domain name to another.

Your Mailchimp-generated CNAME records will look something like this:

Always copy the exact values from your Mailchimp account — these are unique to your domain.

One TXT record — for DMARC

DMARC (Domain-based Message Authentication, Reporting & Conformance) builds on DKIM and SPF (Sender Policy Framework) to tell inbox providers what to do when an email fails authentication checks. It's added as a TXT (text) record — a DNS record that stores plain text information — and a basic version looks like this:

Starting with p=none is the safest approach — it monitors without blocking any mail. As your confidence in the setup grows, you can move to p=quarantine or p=reject for stronger protection against spoofing.

A note on DNS quirks (especially for GoDaddy users)

One of the most common authentication hiccups happens when a DNS provider automatically appends your root domain to the record name. If Mailchimp generated k2._domainkey.yourdomain.com but your provider created k2._domainkey.yourdomain.com.yourdomain.com, your record won't validate. The fix is to enter only k2._domainkey in the Name field and let your provider append the domain automatically.

GoDaddy is a known culprit for this behavior. If your CNAME records aren't validating, this is the first thing to check.

Automatic vs. manual authentication

Mailchimp recommends using Entri for automatic authentication — a tool that connects to your DNS provider and configures all required records on your behalf. No developer needed. Simply select Authenticate your email domain from your Mailchimp home screen to get started.

If you'd rather handle it yourself, choose Or manually authenticate your domain during setup, copy the generated record values, and paste them into your DNS provider's settings. DNS changes can take anywhere from a few minutes to 48 hours to fully propagate, and Mailchimp will notify you by email once everything checks out.

Trick 3: Use an SMTP Service or Dedicated Email Server

The third trick takes your deliverability a step further — particularly useful for businesses sending high volumes of email, managing multiple senders, or sending transactional messages like receipts, booking confirmations, or password resets.

What is an SMTP service, and do you need one?

SMTP (Simple Mail Transfer Protocol) is the standard protocol used to send email across the internet. An SMTP service — like Mailchimp Transactional (formerly Mandrill), SendGrid, or Amazon SES — gives you a dedicated, purpose-built sending infrastructure rather than routing campaigns through a shared server.

The advantages are meaningful: dedicated IP addresses, granular delivery reporting, and much greater control over your sender reputation. For high-volume senders especially, the shared infrastructure of a standard Mailchimp account can become a limiting factor. Note that if you use Mailchimp Transactional, domain authentication (covered in Trick 2) is mandatory before you can send to external recipients.

Why Microsoft 365 is worth considering

For growing businesses or teams with multiple email users, a dedicated email server like Microsoft 365 (formerly Office 365) offers a more robust long-term solution. Microsoft 365 provides professional email hosting on your own domain, with enterprise-grade security, built-in spam filtering, and strong uptime reliability.

When you pair Microsoft 365 with Mailchimp, your DKIM and DMARC records still need to be configured in your DNS settings as outlined above. Microsoft 365 also has its own DKIM signing process, which you can enable directly inside the Microsoft 365 admin portal for an additional layer of authentication.

The compounding benefit here is consistency. Your transactional emails, day-to-day correspondence, and Mailchimp campaigns all flow from the same trusted domain — which builds sender reputation over time and reinforces trust with inbox providers.

Ready to Get Your Mailchimp Setup Right?

These three tricks work best together. A domain-connected email address lays the foundation. Authentication tells inbox providers you're a legitimate sender. And a reliable sending infrastructure ensures your growing list gets every email you work hard to send.

Need help with your Mailchimp setup? We offer setup assistance for clients hosting with us. Reach out through our contact page and we'll let you know the best next step.

Frequently Asked Questions

Do I need to authenticate my domain if I'm only sending a small number of emails?
Yes. While Gmail and Yahoo only mandate DMARC for senders exceeding 5,000 emails per day, authentication improves deliverability for senders of all volumes. Unauthenticated domains are more likely to be filtered as spam regardless of list size.

What's the difference between SPF, DKIM, and DMARC?
SPF (Sender Policy Framework) specifies which mail servers are authorized to send on behalf of your domain. DKIM (DomainKeys Identified Mail) adds a cryptographic signature to verify email integrity. DMARC (Domain-based Message Authentication, Reporting & Conformance) ties both together and instructs inbox providers on how to handle emails that fail those checks.

What's the difference between a CNAME record and a TXT record?
A CNAME (Canonical Name) record maps one domain name to another — Mailchimp uses two of these to configure DKIM. A TXT (text) record stores arbitrary text-based data in your DNS settings — Mailchimp uses one of these to configure DMARC.

How long does DNS propagation take?
Most changes take effect within minutes, but full propagation can take up to 48 hours depending on your DNS provider. Mailchimp will send a confirmation email once your authentication records have been validated.

Can I still send from a Gmail or Yahoo address in Mailchimp?
You can add one, but it creates significant deliverability problems. Free email addresses from public providers cannot be authenticated, making spam filtering far more likely. A domain-connected email address is essential for reliable delivery.

Which SMTP service is best for Mailchimp users?
The right choice depends on your use case. Mailchimp Transactional (Mandrill) integrates natively with Mailchimp and suits transactional email needs. SendGrid and Amazon SES are strong alternatives for high-volume senders who want more control and flexibility over sending infrastructure.