Why Are My Emails Going to Spam in Outlook?

August 3, 2019

Any time that an email marketing campaign has a low open rate and bad performance, you can bet there’s a spam issue involved. In this case we will be dealing with why emails are being labeled as spam in outlook.

The most typical reason for this is the spam filter being used. But this is not the only culprit, there are a number of problems that are likely to affect the detection of your emails as spam.

As a way to give you a more in-depth view of this we can tell you that about 85% of all emails are delivered to the inbox of every email address. This, in itself is good, but it also means that 15% of all emails are labeled as spam or just blocked entirely.

To avoid issues with your emails being labeled as spam you have to know why this happens in the first place.

Why Are My Emails Going to Spam in Outlook
Why Are My Emails Going to Spam in Outlook

Why are my emails going to spam in outlook?

As mentioned there can be a number of reasons for this. Remember, this not necessarily means that your emails are spam, just that they’re viewed as such.

One reason that this might be happening is due to the engagement of your readers. Or it might be due to your IP address, or a long list of reasons. This is why we put extra care in detailing this list of possibilities for you. Below you’ll find the main reasons your emails are labeled as spam email.

Reasons why your emails go to the spam folder in Outlook.

1. You didn’t get permission to email.

Anybody running an email marketing campaign can tell you the following. Never, ever buy a list of addresses. This of course matters when we’re talking about sending campaign emails to uninterested addresses.

Not only the person receiving the email won’t be interested, but it has no idea why that mail got sent to him. Aside from the obvious downfall this would bring to your campaign. It is also, a clear violation of the CAN-SPAM act and the penalties can go as high as 16.000$ for this.

Always build your mailing list yourself and use a clear opt-in to get your subscribers. A double opt-in option might not be a bad idea here, you make sure to filter bad addresses and you get more engaged recipients for your emails.

Make sure to get the approval of the email address you’re sending emails to. This way you can avoid having your emails be labeled as spam.

2. Your IP address was used for spam.

Even when you yourself don’t send any spam email whatsoever, the problem could be that somebody in the past did. This might be the case when you send your emails via an email marketing service. In this case your emails are delivered trough their servers, so if another customer used this service to send spam email, you might be affected by this.

Your deliverability will be affected by the last case, but if things get out of control there might be an even worse scenario. Luckily for you most services take extra care to maintain a great sending reputation.

You do, however, still have to be vigilant for anyone else using your IP to send spam email. A good way to avoid this issue is to rely on a decent and trustworthy email marketing service.

3. You have low engagement rates.

Every ISP out there keeps an eye on your open rate and the engagement of your audience. They will know if your emails are being deleted without being opened. This can lead to the email platform labeling your emails as spam.

This is due to the sheer number of emails that are sent and get deleted without being opened. In other words, your open rate. A low open rate can, not only be bad for your campaign but it can also be critical for the labeling of your emails. For instance, the average open rate for 2018 was 24%, you can be safely around that number. However, if you fall to a 7% to 10% open rate, you’re at risk of having your emails being labeled as spam.

To prevent this, you can actually try to send your emails at a more appropriate time of the day. You can also segment your email list to cater to every group’s interests. Try to generate good subject lines and good content for your emails. However, if the format of the email is the issue, then you'll benefit from our article about the anatomy of the perfect email.

4. Your subscribers don’t remember you.

This is yet another common reason as to why emails get labeled as spam. When you take too long to send emails to your subscribers, they might forget about you. If this does happen, some, if not most, of them will complain about your emails being spam.

Every time a subscriber reports your emails as spam, without the need of your email actually being spam. This complain is taken into consideration by ISPs, and once the number of complaints exceeds a certain value, they take action.

This action often comes in the form of a temporary block for your address. But it can also be the very reason why your emails go straight to the spam folder. This is easy the case of human error, your recipients just don’t remember subscribing to your mailing list.

To avoid this, just be constant and on pint with your mailing schedule. Also, add an unsubscribe link for every email. This is an option for the recipient to not get your emails without harming your reputation.

5. You have a low mailbox usage.

This might sound as something weird for most of you. But it is a very real cause for emails being delivered to the spam folder directly.

The spam filter algorithm used by outlook, and other platforms, do take into consideration the activity of your address. So, having an address that resembles an inactive one might have consequences on your email deliverability.

Also, sending large numbers of emails to many addresses that look inactive is a red flag for spam filters. To avoid this, you have to make sure to keep a clean mailing list at all times.

6. Your subject lines are misleading.

The CAN-SPAM act again, misleading a person using emails can be considered a violation of the regulations. This is not only penalized, but it is also bad for you and your brand’s reputation. Keep in mind that a large number of people feel cheated with the subject lines of the marketing emails they receive.

This is not only the case for emails but webpages as well. None of your content directly sent or advertised, should be misleading in any way. At least not to your subscribers and customers. To avoid this, pay more attention to your subject lines.

7. Your “from” information is inaccurate.

This is also a violation of the CAN-SPAM act. In this case you’re providing fake information to your subscribers. Although this can be often considered an honest mistake, this is actually a valid reason why your emails are being labeled as spam.

Avoiding this, is very easy. Just put your name in the "from" field and make sure that your information is accurate and valid. You can also use your brand’s logo or put your position in the company. This last bit will help you gain more engagement from your audience.

8. You didn’t include your physical address.

Again, a violation of the CAN-SPAM act. In the U.S this goes against the rules of the proper use of email from businesses and companies.

You might want to start leaving your legal address at the bottom of every campaign’s email. For small businesses and people working from home, in order to protect your privacy, you can get a P.O box and use this address instead. For more information on this we do have an article for you. You can read it by clicking here.

9. You didn’t include an unsubscribe link.

By failing to add a clear and valid unsubscribe link with each email, you are at risk of being labeled as spam. This is due to the recipient not being able to make you stop sending emails otherwise.

In the case your subscribers lose interest in your content, then it is a good idea to give them an easy way out. See this as an opt-out feature link that goes at the end of every email. Remember, the sooner uninterested addresses leave your mailing list the better. Since they won’t be labeling you as spam

10. You used spam trigger words.

Some words might be considered a red flag for spam. This is true for both, the content of your email and its subject line. Some of the words and phrases you should avoid are.

  • Amazing.
  • Cancel at any time.
  • Check or money order.
  • Click here.
  • Congratulations.
  • Dear friend.
  • For only ($).
  • Free or toll-free.
  • Great offer.
  • Guarantee.
  • Increase sales.
  • Order now.
  • Promise you.
  • Risk -free.
  • Special promotion.
  • This is not spam.
  • Winner.

These words, and others, are likely to set off the spam filter working with the outlook platform. You can also make sure that your emails pass a spam proof test with ISnotSPAM service. Just click here. Isnotspam.com

11. Your HTML emails don’t follow the best practices.

This is why some emails always end up in the spam folder. Having a good optimization for your emails is very important. For instance, you can use these tips for a better HTML experience.

  • Use a maximum width of 600-800 pixels.
  • Keep your HTML code simple and clean.
  • Keep your image-to-text ratio low.
  • Optimize your images for email.
  • Don’t use obscure fonts.
  • Optimize for mobile.

Most people just take into consideration few of these tips. Implementing all of them is a good way to stay clear from the spam folder in the outlook platform.


Whether or not, you’re having problems with your emails being labeled as spam, information is always key to solve a problem. Now you know why your emails are going to the spam folder in outlook and how to avoid this.

Make sure to get the best out of your time and effort and consider our tips for improving your email marketing campaign. Should you need more assistance in this topic we’re only a few clicks away. From a misused IP address and a violation of the CAN-SPAM act to the actual HTML format of your emails, we’ve got you covered.

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