You've set up your SPF record. You followed the instructions. You're pretty sure you did it right. But your emails are still bouncing, or worse - they're landing in spam. And your email platform keeps telling you your SPF is "failing" or "not fully authenticated."

The frustrating part? SPF failures almost never happen because you're a bad person. They happen because SPF is simpler than people make it sound, and one small mistake tanks the whole thing.

Here's what's actually going wrong - and how to fix it in the next 15 minutes.

The One Mistake That Breaks 90% of SPF Records

Most SPF failures come down to this: you're sending email from a domain you don't actually control the DNS for.

This happens constantly with agencies and service businesses. You're running campaigns from your email provider's infrastructure (Gmail, Outlook, a third-party SMTP service), but you're using your own domain in the "From" address. SPF doesn't care about your intentions. It only checks: "Is the IP address sending this email authorized to send from that domain?"

If the answer is no, SPF fails. Email providers see that and distrust the message.

Here's what your SPF record actually does: it's a DNS record that says "these IP addresses are allowed to send email from my domain." That's it. No magic. If your sending IP isn't listed in that record, you fail authentication.

How to Actually Check if Your SPF Record Is Working

Before you panic, verify what's actually broken. Go to mxtoolbox.com, paste your domain, and run the SPF check. You'll see your current SPF record printed out.

It probably looks something like this:

v=spf1 include:_spf.google.com ~all

The "v=spf1" says this is version 1. The "include:_spf.google.com" tells mail servers to check Google's SPF record and accept IPs they authorize. The "~all" is a softfail - it means "if the IP isn't authorized, still deliver it but mark it suspicious."

Now look at what's actually sending your emails. If you're using Gmail, Google's SPF should cover you. If you're using Lemlist, Woodpecker, or another email platform, you need their SPF include in your record. If you're using a custom SMTP service, you need that IP address explicitly listed.

That mismatch is your problem.

The Fix: Adding Your Actual Sending Service to SPF

Your current SPF record probably doesn't include all the services you're actually sending from. You need to add them.

Here's the structure. You'll go into your domain's DNS settings and update your SPF record to include everyone:

v=spf1 include:sendgrid.net include:_spf.google.com include:servers.mcsv.net ~all

That example includes SendGrid, Google Workspace, and Mailchimp. You'd replace those with whatever you're actually using.

How to find the include you need: go to your email platform's documentation and search for "SPF include" or "SPF record." Every legitimate platform publishes this. Here are the common ones:

Add each one as a separate include. Your record will look like a chain. That's normal.

The One DNS Rule You Can't Ignore

SPF has one hard limit: your record cannot exceed 10 DNS lookups. That sounds like a lot until you start adding includes and suddenly you're hitting it.

Why? Each "include:" is a DNS lookup. If you include Google, Sendgrid, Microsoft, Lemlist, and three other services, you're at 6-7 lookups. If any of those services themselves have includes (and they do), you blow past 10 and SPF fails.

This is where most people get stuck. The solution: consolidate your sending. Pick one email provider. Don't send from Gmail AND Office 365 AND a third-party SMTP. Pick one, set it up properly, and use that.

If you absolutely must use multiple services, use a CNAME redirect instead of includes, but honestly - just pick one.

The Other Thing That Breaks SPF: Hard Fail vs Soft Fail

That "~all" at the end of your SPF record? That's a soft fail. It means "if an IP isn't authorized, still deliver but mark it."

A hard fail looks like this: "-all" instead of "~all". That means "if the IP isn't authorized, reject it completely."

Most people use soft fail for good reason - it's forgiving while you're testing. But here's the problem: mail servers treat soft fail as "maybe spam." They'll still bounce it or spam-folder it if other signals are bad.

Once you're confident your SPF is correct and you've tested it (which we'll cover next), switch to hard fail. It tells mail servers "trust this authentication or reject it." That's stronger.

But only do this after you've verified every service you send from is included in your SPF record. If you miss one and use hard fail, those emails bounce completely.

Actually Test It Before You Deploy

Don't just add your SPF record and hope. Test it.

Send a test email to a Gmail account. Open the message, click the three dots, select "Show original." Look for the SPF authentication line. It'll say "PASS" or "FAIL."

If it passes, you're done. If it fails, your record isn't right yet. Go back to mxtoolbox, verify your syntax, and check that you included the right services.

The syntax has to be exact. No extra spaces. No typos in the includes. "include:sendgrid.net" works. "include:sendgrid" doesn't.

When SPF Alone Isn't Enough

SPF is just one part of email authentication. DKIM and DMARC matter too. If you're doing cold email at scale, you need all three set up correctly. They work together - SPF checks the sending server, DKIM cryptographically signs the message, and DMARC tells recipients what to do if either fails.

If you're seeing SPF pass but still getting spam-foldered, your DKIM or DMARC might be broken. Check those too. We have a detailed guide on SPF, DKIM, and DMARC setup if you want the full picture.

The Real Problem: Infrastructure Is Invisible Until It Breaks

SPF feels like a technical thing - DNS records, server authorization, authentication protocols. But it's actually foundational. You can write the perfect cold email, have the best list, hit the right prospects - and none of it matters if your infrastructure isn't set up to deliver.

Setting up SPF correctly takes 15 minutes. Troubleshooting a broken SPF that's been running for three months costs you hundreds of bounced emails and damaged sender reputation.

The gap between knowing "I need to fix my SPF" and actually having it running correctly at scale - with multiple services, proper DKIM and DMARC, monitoring for blacklists, and maintaining deliverability as you scale - is bigger than most people think. It's not just one DNS record. It's your entire sending infrastructure. That's where most agencies get stuck, and it's what actually determines whether your cold email campaigns land in the inbox or the spam folder.

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