Why your emails get sent to spam

Lately I’ve been noticing it’s harder not to find marketing emails classified as spam, or even miscategorised based on email providers trying to manage email in increasingly complex ways.

There are some obvious reasons for getting your email stuck in the spam folder, but here are some more overlooked ways you might find that happening.

Sending repetitive emails

Can’t think of anything unique that is useful or important? If you can’t think of a good answer then silence is golden.

Writing good content can be hard so it can be worth following an editorial calendar or getting someone in house to dedicate time to writing content for you.

Low open rate

Over time email accounts can be abandoned or the recipient might even loose access for some reason (e.g.: forgetting the password, change of jobs, hacked accounts, etc).

The problem with this is a lot of email providers look at low open rates as a way of signalling how many people want to receive your email. This means if a low percentage of people open your email then the email provider will look at this as a way of suggesting that people don’t want to read your emails or that you have brought an email list (which you shouldn’t do).

This is one reason you should unsubcribe inactive users, meaning if it’s been more than a few months since they last opened your email it might be time to take them off.

People who get unsubscribed can be sent a follow up email requesting they click a link or reply to your email to confirm that they still want to receive your email, because it could be possible the email provider is blocking the information needed to tell you an email has been opened. Just make sure you spread these out over time, because if you end up with a 0% open rate among thousands because of sending them to dead email accounts then that is even worse.

You’re forgotten

If you don’t send many emails out it is possible people will forget about you then mark you as spam thinking they didn’t sign up for your email.

If you are sending them something at least month a month then they’re less likely to forget about you, but even once a quarter is better than not hearing anything from you for months at a time.

Just make sure they’re not repetitive or people wont want to read them.

Not taking advantage of DKIM and similar verification services

Without going into too much detail, DKIM (DomainKeys Identified Mail) is basically a method used for telling email providers that your email address hasn’t been spoofed. It is possible to send email from any email address if you know how to (I wont say how but it’s relatively easy). This is done by spoofing the email address so the person sending it appears to be from someone different to the person who sent it.

Some email sending services do provide this so it’s definitely worth looking into.

It’s not obvious how to unsubscribe

People might choose to unsubscribe for various reasons which aren’t personal. This can include moving, a change in lifestyle, shifting spending habits, or they are just overwhelmed by how much overall email they receive.

Whatever the reason if you don’t make it easy to unsubscribe then people are more likely to mark it as spam because it’s easier and quicker.

High bounce rate

A high bounce rate is another thing email providers factor in to guessing whether someone has likely purchased an email list. Email lists can be purchased and often include a lot of inactive or removed email accounts.

You can use a double opt-in to help balance out the number of bounced emails over time which will make you look better, because it means someone wont receive your email until they click on a link to confirm that they do want to receive your emails. Also if the email account can’t be verified because it has been filtered some other way then you wont keep having to send email to someone who never opens your emails, meaning a double opt in will also improve your open rate.

Using the same email address for non-marketing correspondence

If you are having a direct conversation with someone then you don’t want any important information to be classified as marketing information by services such as Gmail.

With this in mind I would use a different email address for marketing and for everything else use a different email address. It is possible to use a “catch all” (all email forwarded to same email address, so for example marketing@yourwebsite.com, mail@yourwebsite.com and sales@yourwebsite.com could all go to the same email account).

Leaving your contact form unsecured

Do you notice you receive a lot of spam being sent using your contact form? Anecdotally I think the content of all the emails you receive are used by email providers to score the probability of you being a source of spam email, even if you are the one sending them to yourself. Maybe you don’t even read them and immediately delete (another factor email providers use to judge spam, always mark email from your own domain as read), or even worse maybe you mark them as spam (don’t do that).

This is why it’s important to secure your forms with some kind of CAPTCHA service. Most of us have had to enter some distorted text to use a web app or website service to prove you’re human. This is an example of a CAPTCHA being used as protection from spam bots. If you use some kind of CMS or website builder it’s likely you have the option of adding one available, maybe even using reCAPTCHA by Google which works very well. It can even work invisibly and won’t show itself unless it thinks the user seems suspicious which it decides based on a score judged by a number of factors.

When I make forms myself while programming I often create a honeypot in the form of hidden input field. In order the validate the form the input field must be left empty to validate the contact form, so this is one additional layer of invisible security which can help thwart the spam bots.


While there is no “one” magic bullet to keep you out of spam, there are a number of things you should always remain aware of. These can also change over time so pay attention to ensure you can adapt.

There are many resources at your disposal so always best to take advantage of them.

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