Why your emails land in spam (deliverability)

You write a careful email, hit send, and the recipient never replies — because it went straight to their spam folder. Email deliverability problems are frustratingly common. This guide explains what's happening and why.

What is email deliverability?

Deliverability is the ability of your emails to actually reach the recipient's inbox, as opposed to:

• Being filtered into the spam or junk folder
• Being silently rejected by the receiving mail server
• Being "soft bounced" (temporarily rejected) or "hard bounced" (permanently rejected)

Why spam filters exist — and how they work

Spam filters protect people from unwanted, dangerous, or fraudulent email. They analyze every incoming message and assign it a score. A high spam score sends the message to junk. The factors that go into that score include:

• Authentication — does the sending domain have correct SPF, DKIM, and DMARC records?
• Sender reputation — does this email domain or IP address have a history of sending spam?
• Message content — does the subject line or body use spammy patterns ("FREE!", "Act now!", excessive capitals)?
• Engagement history — have recipients previously marked email from this sender as spam?
• List hygiene — is the sender sending to valid, active email addresses?
• Volume patterns — is a new domain suddenly sending thousands of emails?

The most common causes of deliverability problems

Missing or incorrect DNS authentication records

This is the cause we see most often with small businesses. It's no longer just a question of trust, either: Google requires anyone sending to personal Gmail accounts to have SPF or DKIM set up, and requires SPF, DKIM and DMARC from anyone sending more than 5,000 messages a day to those accounts.

See SPF, DKIM & DMARC for email senders for a full explanation, and Email sender guidelines for Google's own rules.

Sending from a free consumer email (Gmail, Hotmail)

Sending business email from yourname@gmail.com rather than yourname@yourdomain.com reduces trust and limits what authentication you can do. See Why not use a free Gmail/Hotmail for business?.

Poor domain or IP reputation

If your domain or the mail server's IP address has ever been used to send spam, it may be on a blocklist. Blocklists are maintained by various organizations and consulted by spam filters. A new domain with no sending history (no "reputation" yet) may also get extra scrutiny initially.

Spam-triggering content or formatting

Some of this is published rule rather than folklore. Google asks senders not to mislead people with the subject line, headers or display name, to keep links visible and understandable, and not to use HTML or CSS to hide content — it says hidden content can get a message marked as spam. It also asks that HTML messages follow HTML standards, which is why a badly built template can hurt even a plain transactional email. Beyond that, our own judgement is that all-caps subject lines, strings of exclamation marks, a missing unsubscribe link and large images with very little text all read badly, so we steer clients away from them. See How to improve email deliverability for the published rules in full.

Sending to outdated or unverified addresses

If you send to a large list that includes many invalid addresses (ones that bounce), receiving servers take note. High bounce rates damage your sender reputation.

Not warming up a new domain or IP address

If you start a brand new domain and immediately send hundreds of emails, spam filters get suspicious. Building up sending volume gradually is called "warming up" your sending reputation.

Your recipient's organization has strict spam filtering

Some corporate email environments are very aggressive. Your emails might be legitimate but still filtered by the recipient's IT policies — in which case, the problem isn't on your end.

Who decides if your email is spam?

Several parties are involved:

1. Your sending mail server — it needs to be correctly configured
2. DNS records — SPF, DKIM, and DMARC tell the world your emails are authorized
3. The recipient's mail server — it checks your authentication and reputation
4. Third-party blocklists — organizations like Spamhaus track known spam senders
5. The recipient themselves — if they've previously marked your emails as spam, that affects your score

Common questions

How can I check if my domain is on a blocklist?

Tools like MXToolbox (mxtoolbox.com) let you check whether your domain or mail server is on common blocklists. Chykalophia can run these checks for you.

A specific recipient isn't getting my emails. What should I tell them to do?

Ask them to check their spam or junk folder first. If they find your email there, they can mark it as "Not spam" or add your address to their contacts — this tells their email provider to trust you.

My transactional emails from my website keep landing in spam. Is that a different problem?

Often yes. Emails sent from your website (forms, notifications, order confirmations) use a different system from your personal email. See Email sent from your website explained and What is SMTP?.

Does the time of day I send affect deliverability?

Not much on its own. A sudden jump in volume can attract scrutiny, but authentication and reputation matter far more than the hour you press send. We haven't seen a small business fix a deliverability problem by changing send times.

Related guides

• How to improve email deliverability
• SPF, DKIM & DMARC for email senders
• Email sent from your website explained
• Transactional vs marketing email
• Email DNS records (MX, SPF, DKIM, DMARC)