Why Your Emails Go to Spam (And How to Fix It)

Run a Blacklist Check

One of the most common reasons emails get blocked is that the server sending your mail has been placed on a blacklist. Think of it like a "do not trust" list that email providers check before accepting incoming messages. If your server's on the list, your emails may be rejected outright — even if there's nothing wrong with the email itself.

This can happen even if you've never sent spam. If you're on shared hosting (which most small businesses are), someone else on the same server could have caused the problem, and everyone sharing that server gets affected.

The good news is it's easy to check. There's a free tool called MXToolbox Blacklist Check that lets you type in your domain and instantly see whether you're listed on any of the major blacklists. If you are, the tool will show you which ones — and most blacklists have a process to request removal.

Watch What's in Your Emails

Spam filters don't just look at who's sending the email — they look at what's inside it. Certain words, phrases, and formatting choices are red flags that can land even a perfectly legitimate email in the junk folder.

Words and phrases that trigger spam filters

There are certain phrases that spam filters have been trained to look out for. Using one or two probably won't cause problems, but packing your email with several of them is a quick way to get flagged. Some common ones include:

• "Act now" or "Limited time offer"
• "Click here" or "Click below"
• "Free" (especially combined with "offer", "gift", or "trial")
• "Congratulations" or "You've been selected"
• "Urgent" or "Important action required"
• "No obligation" or "Risk-free"

This doesn't mean you can never use these words. But if your email reads like a sales pitch from start to finish, don't be surprised if it ends up in spam.

Formatting that looks spammy

Beyond the words themselves, how your email looks can also cause issues:

• WRITING IN ALL CAPS — This is one of the most common triggers.
• Excessive exclamation marks!!! — Keep it professional.
• Bright coloured text — Red and green text in large fonts is a classic spam tactic.
• Emails that are mostly images — If your email is one big image with very little text, filters get suspicious because they can't "read" the image.
• Misleading subject lines — Adding "RE:" or "FWD:" to a brand-new email to make it look like part of a conversation is a red flag.

The simplest advice? Write your emails the way you'd write a professional letter. Clear subject line, normal formatting, and a natural tone.

Be Careful What You Forward

This one catches a lot of people off guard. You receive a dodgy-looking email, and you forward it to a colleague saying "Hey, is this legit?" — but the spam filter on the other end doesn't know you're just asking a question. It sees the spammy content inside the forwarded email and blocks it.

The same thing happens with chain emails or emails that have been forwarded multiple times. Each forward adds more headers and content, and by the time it reaches the next person, it looks suspicious enough to get caught.

If you need to share a suspicious email with someone, take a screenshot instead, or just describe what it says in your own words. That way the actual spam content never touches the other person's inbox.

Other Common Culprits

Beyond content and blacklists, there are a few other things that can quietly hurt your email deliverability:

• Sending too many emails at once — If you normally send a handful of emails a day and suddenly blast out hundreds, that looks suspicious. If you're doing email marketing, ramp up gradually rather than going from zero to a thousand overnight.
• Emailing old or invalid addresses — When a lot of your emails bounce, it signals that you're not keeping your contact list clean — which is something spammers are known for.
• Large attachments — Oversized files can trigger blocks. Rather use a link to Google Drive, OneDrive, or Dropbox for bigger files.
• Shortened links — URL shorteners like bit.ly hide where the link actually goes, which spam filters don't like. Use full links where you can.
• Too many links in one email — An email packed with links looks like a marketing blast or, worse, a phishing attempt.
• Domain authentication issues — Your domain has behind-the-scenes settings that help email providers verify your emails are legitimate. If these aren't set up properly, your emails are more likely to get flagged. Your hosting provider or IT person can check this for you — it's usually a quick fix on their end.

It Might Not Be You

Sometimes you've done everything right and the problem is on the other person's side. Their company might have very strict spam filters, or they may have accidentally marked one of your emails as spam in the past — which trains the filter to keep blocking you.

Other times their mailbox is simply full, or they have inbox rules that move emails to folders they never check.

If you suspect this is the case, try reaching out through another channel — a quick phone call or WhatsApp message — and ask them to check their spam or junk folder. Once they find your email there, they can mark it as "Not Spam" which helps future emails get through.

Ask Them to Whitelist Your Domain

If there's a specific client or contact who consistently isn't receiving your emails, the most reliable fix is to ask them to whitelist your domain. This simply means telling their email system "always trust emails from this address" — it bypasses spam filters entirely for your messages.

There are a few ways they can do this:

Quick-Fix Checklist

Here's a quick summary of things you can check right now: