Email deliverability: 10 things landing your emails in the SPAM folder

email deliverability banner image


For marketers, email deliverability is hugely important. Trillions of emails are sent each year and email marketing remains a cost-effective resource for driving conversions – especially for those who work hard to optimize their campaigns and personalize their messages.

But nobody can read your marketing emails if they’re banished to the spam folder. Poor email deliverability can damage your reputation, impacts trust in your brand, and reflects badly on your business. No marketer wants to see their emails sent into exile, but the simplest of slip-ups can result in exactly this.

To improve email deliverability, here are 10 ways to ensure that your messages make it to the inbox of your audience:

1. Low engagement rates

If your newsletters have a low open rate, spam filters can be triggered, causing your messages to be flagged as spam.

A leading contributor to a low open rate is when an email is deleted without being opened. Some of the biggest email providers have acknowledged that this action prompts emails to end up in the spam folder.

Gmail, which has about 300 million active users worldwide, looks at open, reply, and forward rates to indicate the level of engagement readers have with emails. This is what its algorithm uses to determine what is flagged as spam.

There are a few simple steps you can take to boost engagement and, in turn, help make sure your emails make it to your audience’s inbox:

  • Subject lines – Keep them short.
  • Email frequency – If your open rates are decreasing, cut back on the number of emails you send. Sometimes, less is more.
  • Timing – At the minimum, be sure your audience is awake when you send an email! But go further by testing what days and times prove most engaging.
  • Update your mailing list – Go through your lists and cut unengaged contacts.
  • Segment your mailing list – This allows you to send the right content to the right people. Personalizing your emails will increase open rates.

2. Sending out emails with a misleading subject line

We’ve all been fooled into clicking an email with a misleading subject line. Not only does it dissipate trust between you and your audience, it also violates American anti-spam laws.

The CAN-SPAM regulations set out the rules for email marketing and deceptive headlines are a big no-no. For every single email sent breaking these rules, the sender is subject to a penalty of up to $41,484.

Using misleading subject lines also hurts your brand image, annoys subscribers and can have a negative impact on your email deliverability when they are flagged as spam.

email deliverability survey results
via Litmus

The key takeaway? Be honest. Use the subject line to indicate what your email is about and to highlight the value it will bring to users who click-through.


3. Including spam trigger words

Though spam filters have become much more sophisticated, it’s still a good idea to avoid certain words in your email subject lines.

There are comprehensive lists of SPAM trigger words available over on HubSpot and Prospect.io’s blogs. They’re definitely worth checking out and if you spot any words that your business is at risk of using, communicate this with your team.

Some of the most common SPAM trigger words include:

  • Congratulations
  • Click here
  • Dear friend
  • Risk free
  • This isn’t spam
  • Order now
  • Increase sales

You can also use a free tool called ISnotSpam, which tests your email content and tells you if it is likely to trigger spam filters and damage your email deliverability.

So, dear friend, if you happen to be a Nigerian prince, it’s probably best to refrain from telling people by email.

4. Not using a reputable email service provider

If your IP address becomes associated with spam, then this can seriously damage your chances of reaching the inbox. But when you use an email marketing service, your emails will be delivered through their servers and if another user sends spam, this could affect your email deliverability.

Be sure to use a well-known email provider which has a strong anti-spam policy and works hard to maintain a trustworthy reputation. MailChimp and Campaign Monitor are both good choices – check out our best marketing tools list for some other options.

5. Having inactive email accounts on your lists

As we’ve already mentioned, it’s a good idea to do a clearout of your mailing lists every now and then. Beyond affecting open rates, sending messages to inactive accounts can catch the attention of spam filters.

Some service providers, like AWeber, automatically keep this in check and will eventually stop sending emails to accounts which your emails bounce or can’t be delivered to.

Remember, having a smaller, more engaged email list is far better than a large one made up of a disengaged audience.

6. Not including an unsubscribe link

Even if your most recent newsletter was pure gold, you still need to include an unsubscribe option at the bottom. If you don’t, this can lead to complaints – or even some hefty fines from the FTC.

It’s also important to note that if someone requests to be removed from your list, this has to be done within 10 business days.

To get information as to why someone unsubscribed, it is a good idea to provide a handy feedback form after their opt-out is confirmed. This will help you improve future emails and your approach to email marketing.

email deliverability opt out feedback form example

7. Using unauthenticated email addresses

This probably goes without saying, but you should use a branded email address for your business communications. Not only does it look more professional, build trust with your audience and showcase your brand, but it also improves the deliverability of your messages.

You just need to take a look in your spam folder to see that lots of emails coming from generic addresses end up here – even if the person who writes them claims to represent a legit business.

email deliverability example of branded email address

8. Not including your company address

Including your company’s postal address is a great way to build trust with your audience and inspire confidence in prospects – but it is also one of the steps necessary to make your marketing emails CAN-SPAM compliant.

Most marketing email services will allow you to set up a footer, which will feature your address at the bottom of all outgoing messages. You can also use this opportunity to stand out and show off your brand’s personality.

email deliverability and address

9. Complaints of SPAM

We’ve already highlighted that you shouldn’t use spam trigger words or misleading subject lines, but this won’t guarantee safe passage for your emails. You need to ensure the content of your emails won’t be mistaken for junk mail, as complaints will hurt your deliverability chances.

To prevent mix-ups and damaging your email deliverability, make sure to showcase your brand on your emails so people who signed up don’t forget who you are. This will prevent your messages from accidentally being flagged as spam.

Under European GDPR laws, it is necessary to get permission to contact someone by email before adding them to your lists. So once they’ve opted in, it’s a good idea to send a confirmation email to familiarize new sign-ups with your brand’s emails. This will help build trust and visibility too.

email deliverability spam filter

email deliverability issues

10. Using generic short links

Generic short link services are used by millions of people but, in recent years, they have become associated with spam and malicious content.

Why? Well because spammers do actually use them to trick people into clicking on their content. They take advantage of the fact that generic links don’t indicate what the final destination will be.

But even genuine links – often created by marketers who want to track their links – can be distrusted. Generic short links can be blacklisted and, if you use them, this will impact your email deliverability negatively.

email deliverability and blacklists

However, if you use branded links, which feature your own domain, this isn’t an issue. Nobody else will be able to create links using this domain, so it won’t become associated with spam or malicious content.

Use Rebrandly to create on-brand, trustworthy links which showcase your brand’s name and boost the deliverability of your marketing emails.

Improving email deliverability going forward:

If you follow these 10 simple steps and best practices, it will help ensure the deliverability of your emails.

Getting them to your prospects an essential step in a successful email campaign. So make sure to set up unsubscribe buttons, use a reliable service, implement branded links and familiarize your team with spam triggers.

Tracking your email’s performance and engagement metrics can alert you to what is working, what needs improvement and when your lists need to be cleared. Keep track of open rates and add UTM parameters to your email links to know exactly what connects with your audience. You can find more useful information about the journey of an email, how can ISPs affect email deliverability or what determines sender reputation in the ultimate guide to mastering email deliverability.

Further Reading:

This Article is About:

  • How to avoid emails going to spam
  • Email deliverability best practices
  • Ensuring email delivery
  • Email marketing deliverability

Photo in main image by Chris Kristiansen via Unsplash

Originally posted: August 21, 2018

Republished: March 6, 2020

Louisa works on putting together creative and useful content for Rebrandly customers to read. Though she spends a lot of time reading and writing online, she still loves to buy the Sunday papers.