Why are my emails landing in the spam folder?

Why are my emails landing in the spam folder? - mailmonitor

Email marketers spend countless hours trying to perfect their content before they decide to send them out to their audience. However, there are spam filters and email authentication protocols in place that can hinder messages from being received by readers in the first place.

In fact, many of their emails not only fail to reach their target destinations but are being sent directly to the spam folder. The good news is that there are ways to improve your email deliverability rate and minimize the chances that an email lands in the spam folder.

In this post, we’ll discuss the main reasons why emails land in the spam folder, how you can avoid being flagged as spam, and some of the best practices so that you can minimize the chances of being considered spam-like by various email entities.

Main Reasons Why Emails Land in the Spam Folder

Spam filters have been monitoring and purging the internet of spam for many years. These filters have gradually become more complex by applying the latest algorithms as spam continues to be a huge problem.

With spam filters using various email authentication and domain reputation analysis criteria, your messages can be sent to the spam folder for many reasons. Knowing what these reasons are and understanding what you did wrong can lead you in the right direction in fixing your email campaigns.

Here are 12 common reasons why your emails are sent to the spam folder:

Reason #1: You Have a Low IP Reputation

Your IP reputation can be significantly affected especially when you’re working with others using the same IP address. Shared IP address configurations for email could be ideal when you want to save on cost, but it can have significant drawbacks in the long run.

This is because when a shared IP address receives negative feedback from anti-spam organizations and mailbox providers, you also become affected by these consequences. Senders who are practicing bad email habits will cause you to deal with the problems when your emails start landing in the spam folder.

When you’re on a shared IP address, you’re at the mercy of other senders and their email practices.

Reason #2: You Have Poor Domain Reputation

The reputation of the domain you’re currently using has a big effect on how your emails perform once they are sent out. Spam filters and email service providers analyze your domain reputation to see how trustworthy you are as a sender.

When they see that you have a poor domain reputation, your emails can end up in the spam folder instead of going straight to the inbox. When you have a bad enough reputation, everything from shipping notifications to order confirmation emails can be blocked outright.

In other words, a bad email reputation could make your brand invisible in the world of email marketing.

Reason #3: You Didn’t Ask for Permission from Recipients

There are laws such as the CAN-SPAM Act that require senders to obtain permission before they can send emails to their recipients. This means that harvesting email addresses to grow your mailing list is illegal. Even if it wasn’t illegal, though, it’s still not a recommended practice — it leads to poor targeting and engagement.

Such laws also requires people who have subscribed to your email lists to provide you with explicit permission that they want to receive your emails. Opt-in forms or disclaimers during account creations can allow people to indicate that they are willing recipients.

The same goes in reverse as well. If someone specifically requests that they don’t want to receive emails from you anymore, then you don’t have their permission. Continuing to send emails is counted as spam — and a violation of the law.

Reason #4: You Haven’t Authenticated Your Emails

The purpose of email authentication is to authorize a service so it can let you send messages on your behalf. Despite being sent by a third-party provider, the domain name you use will be attached to the information provided whenever you send emails.

If you haven’t authenticated your emails or did so poorly, then this will be counted against you.

There are several forms of email authentication protocols available today. The most common of these records are Sender Policy Framework (SPF), DomainKeys Identified Mail (DKIM), and Domain-Based Message Authentication, Reporting & Conformance (DMARC).

SPF provides email senders with a verification that their IP addresses are approved to send messages. DKIM works by providing a digital signature and encryption key to verify emails. Meanwhile, DMARC is a combination of both SPF and DKIM, providing the best of both protocols.

Reason #5: Your Emails Lack an Unsubscribe Link

As mentioned, laws such as the CAN-SPAM Act require all marketing emails to have a clear unsubscribe link. Whenever someone decides to unsubscribe from your newsletter through these links, senders are required to process these requests in 10 days. You also need to make the process easy to follow.

For email senders, adding an unsubscribe link to their messages can seem like a bad thing to do. After all, why would you want people to trickle out of your mailing list when you should be bringing them in?

However, providing users with a smooth way to get out of your subscriber list lets everyone know that your brand can be trusted. It also makes your analytics more accurate, since you know your emails are only going to subscribers who are interested enough to stay subscribed.

But when you hide your unsubscribe links or make it difficult for people to stop receiving emails from you, you not only frustrate your recipients — you’ll also catch the eye of anti-spam organizations, which can lead to dire consequences.

Reason #6: You Keep Sending Emails to Clients Who Are No Longer Engaged

Mailbox providers and spam filters are designed to filter emails that their users aren’t interested in. They look to subscriber activity to help them decide which messages are worth keeping and which ones should be marked as spam.

The actions of your subscribers – when they open or delete your emails – are all recorded by these entities. When you have a low open rate and engagement rate, your messages are at risk of being sent to the spam folder.

Reason #7: You’re Sending Too Many Emails

As a marketer or business owner, it’s only natural to have an urge to promote your brand around the clock. There are many things that you can’t wait to share with your audience, from new product launches to content to discounts.

However, your email subscribers and existing consumers aren’t thinking of your company the same way you do. These people have other important things to think about, and they don’t want to hear from brands all the time.

Sending promotional emails at a high frequency is counterproductive and doesn’t help your cause. Over time, you will frustrate your subscribers. No matter how much they enjoyed your emails in the beginning, they may be motivated to unsubscribe when there are constant emails coming their way.

Because of this, you want to limit the messages you send to just once a week at most.

You can also change your sending frequency depending on what your subscribers prefer. Setting up your opt-in forms to include how often people want to receive your emails is one great way to obtain feedback and make your audience satisfied. For example, some of your subscribers may want updates twice a week, while others prefer being emailed only once a month.

From there, you can use email segmentation to send emails the appropriate number of times.

Reason #8: Your Messages Might Be Perceived as Spam

Besides monitoring sender reputation, spam filters also keep an eye out for emails that contain certain terms. Emails that have reached a threshold of using such words can end up in the spam or junk folder.

Some of the most common spam trigger words are:

  • Easy money
  • Free
  • No cost

You also need to pay attention to certain conventions, including:

  • Sentences with multiple exclamation points
  • Words that are in all caps
  • Improper grammar

Generally speaking, these are the email habits that are often used by spammers. Although using just a few of these words every now and then doesn’t automatically mean you’ll get flagged, having too many of them can lead to that.

Reason #9: You Have Misleading Subject Lines

One of the first impressions that people get when they view a message is its subject line. As a marketer, it’s only natural to ensure that this area will grab their attention and encourage users to access your email.

However, honesty is also important when crafting subject lines. Not only is using a misleading subject line a bad practice, but it’s also illegal to do so based on the CAN-SPAM Act.

This will happen regardless of your intentions. Even if you don’t intend to deceive your audience, if the subject line is unclear, they may still think it’s not related to the content and flag it as spam.

Using subject lines beginning with “RE:” is a technique you should avoid using unless you’re actually responding to that contact. In a similar fashion, having “FW:” in your subject can be misleading as people would think you are one of their known contacts.

Additionally, you should make sure that your subject lines are professional. This means that your content should have no spelling and grammar errors and should not be typed in all capital letters.

Ultimately, you should ensure that your subject lines deliver what it promises to your recipients. Failing to fulfill such a promise puts your IP or domain reputation at risk of being flagged as spam.

Reason #10: Your Emails Aren’t Well-Designed

Text-only messages have their own distinct advantages but they may not be the best choice for brands in specific sectors like in eCommerce. Emails that contain images, branding, and other HTML components can be quite effective when used properly.

However, it’s crucial that you follow some basic rules when you choose to incorporate HTML in your emails. Failing to do so can easily result in your messages going to spam folders. For example, you need to design your emails in a way to make them easy-to-read. Make sure you’re using fonts that are readable on multiple devices, and that your backgrounds contrast from the text enough. For example, putting white text on a light blue background is difficult to read. If your subscribers can’t read your emails, they will most likely mark it as spam.

Emails that consist mostly of text are a good idea since you want to minimize using HTML as much as possible. You can still ensure your branding stands out without having to go overboard.

Reason #11: Your Email Contains Too Many Attachments

Anti-spam organizations consider attachments a huge red flag, especially when you send them in bulk. This is the case because, historically speaking, most viruses are sent through email attachments.

As an email marketer, you want to minimize adding attachments to your emails as much as possible or simply avoid it. If you have to send an attachment, ensure that all of your recipients know about this ahead of time. You want to minimize attaching files to just one document per email.

A safer option to include a file or document in your email is to upload it to a reputable cloud storage service provider like Dropbox or Google Drive. From there, you can paste the link into your email. Your subscribers get to access your content, and you avoid triggering spam filters in the process.

Reason #12: Your Contacts Flagged Your Messages as Spam

Out of all reasons why emails land in the spam folder, the most obvious is when your recipients mark your emails as spam. Even when you craft compelling content, and your contacts have given you permission to send messages, they can still readily flag your email as spam as a means to de-clutter their inbox.

It could also be because people did it by accident or have already forgotten why they are subscribed to your email list in the first place. The bad news is that once a certain threshold of your emails has been flagged as spam, your email address will eventually be placed under the watchful eyes of spam filters.

These entities will begin diverting your messages to spam even when you follow the best email marketing practices. Your messages can look like spam even if users have already stopped flagging your emails.

Although being marked as spam is totally out of your control, you can still skew the odds in your favor by ensuring the content you distribute is top-notch.

Best Tips to Avoid Having Your Emails Marked as Spam

Now that you are aware of the most common reasons why an email lands in the spam folder, it’s time for you to learn the best practices to avoid getting there in the first place.

Here are the best tips to avoid being marked as spam:

Tip#1: Ask Your Contacts to Whitelist Your Email Address

Popular mailbox providers like Yahoo!, Microsoft, and Google are constantly working to make sure that the algorithms and spam filters they use don’t flag messages coming from people their users know. This is because they readily assume that when an email is sent from someone in their contacts list, it’s most likely not spam.

Such privileged treatment can be beneficial to email marketers, which is why you should secure it right away. One way of doing this is to ask your recipients to include your email address to their whitelist or add you as a safe sender.

It’s best that you provide them with instructions in your email so that they can do it right away. Using screenshots to illustrate how to get it done can be highly effective.

A great place to insert this whitelist request is when you first send a welcome email to someone who recently joined your mailing list.

Tip #2: Comply With Email Marketing Laws

Concerning email etiquette, it’s crucial for every email marketer to know the laws about email marketing. The CAN-SPAM Act is one of the most important for you to be familiar with since it outlines all of the rules you need to follow when distributing commercial messages.

Memorizing every line isn’t necessary, but it’s crucial that you’re aware of the severe penalties that come with spam emails. The CAN-SPAM Act defines spam-like email as:

  • Emails that use misleading headers and subject lines
  • Marketing emails that aren’t clearly identified as ads
  • Emails without a valid physical address included
  • Emails that don’t have a simple means of opting out

In addition, you need to:

  • Honor opt-out requests within 10 business days
  • Monitor third-party organizations and the content they are sending on your behalf

The good news is that most modern and reputable email marketing platforms today make sure that their users comply with these rules as a default. However, it is best to double-check any information you have to enter manually.

Tip #3: Remove Inactive Contacts from Your List

An important metric that spam filters use to identify spam-like messages is by assessing how active and engaged your subscribers are. If they see that your mailing list has a low engagement percentage, they will see this as an indication that your content isn’t worth opening and could be spam.

A great way to make sure that this doesn’t happen is by taking out inactive email addresses in your mailing list. People who haven’t interacted with your emails for quite some time are ideal candidates for removal.

Another option would be to send them a retargeting campaign. Emails from such a campaign are designed to bring users back and encourage them to re-engage with your content or opt-out if they prefer. Either way, you’ll have an email list with only engaged users on it.

Tip #4: Send Emails Regularly

As mentioned, you should never send emails too often. However, there is a caveat to this — if you only activate your marketing email campaign once or twice a month, you risk your subscribers forgetting why they subscribed to your newsletter. When this occurs, they could unsubscribe to your list, or worse, flag all subsequent messages from you as spam. This is why sending emails once a week or according to your subscribers’ preferences is a good rule of thumb to follow.

Combine this regularity with a commitment to providing value to your readers whenever you send them emails. Sending high-quality content regularly will give your emails the highest chance of being memorable.

Tip #5: Be Honest With Your Contacts

As you already know, you should never make your emails deceptive according to the CAN-SPAM law and email best practices. That’s why you should avoid using tricky subject lines and always provide what you promised to your readers.

In addition, avoid subject lines that use overly complex words or are difficult to follow. Otherwise, your emails may be perceived as deceptive even if you didn’t intend for them to be.


There are numerous reasons why emails end up in the spam folder. These can range from not asking permission to using spam triggers to designing poor subject lines.

Other reasons include:

  • Having low IP and domain reputation
  • Your messages lack the proper email authentication
  • You don’t have an unsubscribe link in your emails
  • You continue sending to inactive subscribers
  • You email infrequently
  • You use misleading subject lines
  • Your emails aren’t well-designed
  • Your email has too many attachments
  • Subscribers flagged your email as spam

No matter the reason, it’s vital that you resolve any issues with being flagged as spam quickly. Failing to do so will result in a lower sender reputation in the eyes of mailbox providers and anti-spam organizations.

Email marketers should maintain a reputable standing among these entities if they want to ensure their messages reach their intended destinations. That’s why we’ve also shared with you some of the best practices that you should follow for successful email marketing.

When you can address your spam problems as soon as possible, you can give your messages the highest chance of staying out of spam folders. Furthermore, these email marketing practices are designed to increase the overall impact of your messages to convert more users into paying customers.

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