Why Your Emails Are Landing in Spam (And How to Fix SPF, DKIM & DMARC)

Most businesses discover their emails are going to spam only when a client mentions it — by which point dozens of messages and potential deals have already been silently rejected. The good news: email deliverability issues are almost always fixable with the right DNS configuration.

What is email deliverability?

Email deliverability is the measure of whether your emails actually reach your recipients' inboxes, as opposed to their spam or promotions folders. It's determined by a combination of technical authentication records, your sending reputation, and the content of your emails.

Why do emails go to spam?

The most common cause is missing or misconfigured email authentication records — specifically SPF, DKIM, and DMARC. Without all three, receiving mail servers have no way to verify that you are who you say you are, so they treat your emails with suspicion.

What is SPF (Sender Policy Framework)?

SPF is a DNS TXT record that lists all the servers authorized to send email on behalf of your domain. When a receiving server gets an email from you, it checks your SPF record to confirm the sending server is on your approved list. If it isn't, the email fails SPF — and may be marked as spam.

What is DKIM (DomainKeys Identified Mail)?

DKIM adds a cryptographic signature to every email you send. The receiving server checks this signature against a public key in your DNS. This proves the email hasn't been tampered with in transit — a critical spam filter signal.

What is DMARC?

DMARC ties SPF and DKIM together with a policy: it tells receiving servers what to do with emails that fail authentication — either do nothing (p=none), quarantine them (p=quarantine), or reject them outright (p=reject). Without DMARC, even a valid SPF and DKIM setup leaves you vulnerable to domain spoofing.

How long does it take to fix email deliverability?

In most cases, correct SPF, DKIM, and DMARC configuration resolves deliverability issues within 24–72 hours. DNS changes propagate globally within that window, and your sender reputation begins improving as soon as authentication passes consistently.