Your cold email campaign is running. The copy is solid. Your list is clean. And then you check your dashboard and see it: deliverability is tanking, and half your emails aren't even making it to inboxes.
You Google "DMARC failing" at 11 PM on a Tuesday. The results are a mess of technical jargon that makes your head hurt. SPF, DKIM, alignment issues, policy enforcement - it all sounds like alphabet soup.
Here's the thing though - if your DMARC is failing, your emails are probably ending up in spam. And if they're in spam, they're not getting opened. And if they're not getting opened, your campaign is dead in the water.
Let me walk you through what's actually happening and how to fix it.
DMARC stands for Domain-based Message Authentication, Reporting and Conformance. Forget the name. What it actually does is tell email providers whether emails coming from your domain are legit or not.
Think of it like a bouncer at a club. The bouncer (email provider) gets an email claiming to be from your domain. DMARC is the ID that proves it's actually you and not some imposter sending spam under your name.
If your DMARC is set up wrong or failing, the bouncer gets suspicious. And when the bouncer gets suspicious, your email ends up in spam or bounces entirely.
SPF - Sender Policy Framework - is basically a whitelist. It tells email providers: "These are the servers allowed to send emails from my domain."
If you're sending cold emails through a service (like an ESP) and you haven't added that service's servers to your SPF record, DMARC fails because the email didn't come from an "approved" server.
The fix: You need to add your email service's SPF record to your domain's DNS. This usually looks something like:
v=spf1 include:sendgrid.net include:your-esp.com ~all
That "~all" at the end means softfail - basically, "these are approved senders, and everything else is suspicious." Some people use "-all" (hard fail), which is stricter but can cause issues if you're not careful.
If you're not sure what to add, check your ESP's documentation. They'll tell you exactly what SPF record to include.
DKIM - DomainKeys Identified Mail - adds a digital signature to your emails. It's cryptographic verification that the email actually came from you.
When email providers receive your message, they check that signature. If it verifies, great. If it doesn't, that's another red flag for DMARC.
Here's the catch: your ESP usually generates DKIM keys for you. But you have to add them to your domain's DNS. If you haven't done that, DKIM isn't working.
The fix: Go into your ESP's settings, find the DKIM section, copy the DNS records they provide, and add them to your domain. This is usually a one-time setup that takes 10 minutes.
Once you add it, there's a verification step. Your ESP will check if the DNS records are live. Once they verify, you're good.
This is the sneaky one. You can have SPF and DKIM set up perfectly, but if they're not "aligned" with your domain, DMARC still fails.
Alignment means the domain in the email's "From" header matches the domain you authenticated with SPF or DKIM.
Example: You're sending from [email protected], but your DKIM is signed with mail.sendingservice.com. Those don't match, so alignment fails.
The fix: Make sure your "From" address is your actual domain, not a subdomain of your ESP. Some ESPs let you customize this. If yours doesn't, you might need to switch services or set up a dedicated sending domain.
Don't just guess. Use tools to verify:
Run these checks after you make changes. Don't just hope it's working.
Here's what I see most often: someone sets up SPF and DKIM, but they're not configured to work together. They're treating them like separate things when they should be one unified system.
Or - and this is common - they set everything up on a subdomain for sending and a different domain for the "From" address. Email providers get confused. DMARC fails.
The solution is consistency. One domain. One sending service. One set of authentication records. Simple.
If you're running a cold email campaign and your DMARC is failing, you're leaving money on the table. Emails that should be landing in inboxes are going to spam. Reply rates plummet. The whole campaign becomes a waste of time and budget.
Fixing this is non-negotiable if you want cold email to work.
That said - this is the kind of thing that takes time to get right. You have to understand DNS, coordinate with your ESP, test everything, wait for propagation, and troubleshoot when something doesn't work. It's technical, tedious, and easy to mess up.
A lot of agencies and service businesses try to handle this themselves and end up spending days on it. If that sounds like you, and you'd rather have someone else deal with the infrastructure side while you focus on actually running your business, that's exactly the kind of thing we handle at BEC Growth. We set up all the authentication, manage the sending infrastructure, handle the campaigns, and make sure everything actually lands. You just get the clients.
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