Why Are My Emails Going to Spam?

Why Do Emails Go to Spam?

If your emails are landing in the spam folder instead of the inbox, there are specific reasons — and each one has a fix. Mail servers use dozens of signals to decide whether an email is spam. The key factors fall into four categories:

1. Missing or incorrect authentication configuration (SPF/DKIM/DMARC)
2. IP address or domain on a blacklist
3. Email content that triggers spam filters
4. Problems with the mail server or sending infrastructure

Check 1 — SPF, DKIM and DMARC

This is the most common cause. If SPF or DKIM are missing or failing, mail servers cannot verify that you sent the email.

What the results mean:

• SPF: fail / none — your mail server is not authorised to send for your domain. Add it to the SPF record.
• DKIM: fail — the digital signature cannot be verified. Usually means the DKIM TXT record is missing or incorrect.
• DMARC: fail — neither SPF nor DKIM pass AND there is no alignment with the From: domain.

Check 2 — Blacklists (DNSBL)

If your mail server's IP address or your domain appears on one or more email blacklists, emails will be rejected or routed to spam automatically — regardless of your authentication records.

How do you end up on a blacklist?

• Your server has sent spam in the past (or is being used by others to send spam)
• You're on shared hosting and a neighbour sender has problems
• Many spam reports have been filed against emails from your domain
• An open relay or misconfigured mail server that accepts mail from anyone

What to do if you're blacklisted:

1. Find out which lists you appear on
2. Fix the root cause first (spam that was sent, open relay, etc.)
3. Visit the delisting page for each list and submit a removal request

Check 3 — Email Content

Even with perfect authentication, the content itself can trigger spam filters:

• Spam trigger words: "free", "you won", "CAPITAL LETTERS", excessive exclamation marks
• Too many links or images: Especially if the image-to-text ratio is very high
• Broken HTML markup: Poorly written HTML looks suspicious to filters
• Missing unsubscribe link: Required for bulk email (GDPR + anti-spam laws)
• Broken links or links to blacklisted domains

Check 4 — Mail Server Configuration

Reverse DNS (PTR record)

Your mail server's IP address must have a reverse DNS entry that matches the hostname. If the server IP doesn't resolve back to a hostname, many mail servers reject emails automatically.

HELO/EHLO hostname

Your mail server must identify itself with a fully qualified hostname (FQDN) that matches the PTR record of its IP address.

Port 25 vs 587/465

If you're sending from shared hosting or a cloud provider, make sure port 25 isn't blocked (many providers close it). Use port 587 (STARTTLS) or 465 (SSL) for submission.

Checklist — Step-by-Step Resolution