Top 7 Reasons Why Your Emails Are Going to Spam

Email marketing is an extremely effective way to gain the attention and reach of target audiences- if it is done the right way. The ultimate goal with email marketing is to stimulate high engagement and drive high conversion rates. There are many reasons why your emails could be going to a spam folder. If emails do […]

Email marketing is an extremely effective way to gain the attention and reach of target audiences- if it is done the right way. The ultimate goal with email marketing is to stimulate high engagement and drive high conversion rates.

There are many reasons why your emails could be going to a spam folder. If emails do not adhere to certain guidelines, they can damage the reputation of the sender as well as waste valuable time and resources, leading to poor email deliverability. In this article, I will examine the main reasons why emails are booted to the spam folder and show you how to write better emails.

Before we dive in, I will provide some context on how spam folders work. There are a few key phrases to familiarize yourself with in order to best understand how email infrastructure works.

  • Email Service Provider: Email Service Provider. These are companies like MAPS that offer marketing software that includes tools to help send, receive, and manage emails.
  • IP Address: Internet Protocol Address. Normally managed by the ESP, it is the unique identification of the server over which your emails are delivered.
  • Inbox Providers: These are companies, such as Microsoft Outlook, Google Gmail and Yahoo Mail that provide an inbox for your emails.
  • Firewalls: Provides security by monitoring data and determining what to allow and what to block on your network.

Spam continues to be a prevalent issue. In order to face the problem, ESPs and Internet Service Providers utilize spam filters and Firewalls to keep unwanted spam emails out of your inbox.

1. Email content is “spam-like”

Use of spam trigger words

It is important to use straightforward, natural language when composing marketing emails. Using words classified as pushy or negative are considered to be spam signals. Examples of spam trigger words include “Win,” “Free,” or “Exclusive Offer.”

Grammatical & spelling errors

Poorly written emails are almost always a dead giveaway of a spammer. It is crucial that you always re-read your emails and check that the spelling and grammar is correct. You also need to format the copy of the email in a way that is easy to navigate for the reader. Avoid big fonts, flashy colors, and lots of symbols such as $$$$$, !!!!!!, # and “% off.”

Links & URLs

Beware of suspicious or fraudulent domains and URLs. If the links embedded inside your email point to these, it will certainly be flagged as spam.  Never use generic links or URL shorteners in your emails. This is due to the fact that many spammers use shortening services to hide their spam-like URLs.

2. Email design does not follow protocols    

Use of Images

Always be sure to optimize your text-to-image ratio, avoid sending image-only emails, and  use alt text when embedding images. This is because spammers use images to hide their spam trigger words, while filling the body copy of the email with neutral words. Therefore, an email with a skewed image to text ratio can become flagged by spam filters. Mailchimp recommends following an 80:20 text to image ratio in emails (80% text, 20% image). However, Hustler Marketingsuggests keeping a more balanced ratio, such as 60:40 or even 50:50. 

HTML & JavaScript

Email HTML is different from Web HTML. Many obvious HTML tags are not supported by major ESPs such as Outlook.  Avoid using any type of script in your emails, as this will cause your emails to be flagged as spam. This also means that you need to avoid embedding forms in your emails as well. The “Submit” button of a form requires the use of JavaScript, which is an issue.

Missing Key Elements

Always make sure your emails include the key elements of:

  • From (name)
  • Subject line
  • Email body 
  • Plain text version in your email
  • Unsubscribe Link

3. Violation of spam laws

Not Including an Unsubscribe Link

Email marketing regulations, such as the CAN-SPAM Act, require that all marketing emails need to have a clear way for users to opt-out of receiving them. This is done by including an unsubscribe link, typically at the bottom (footer) of your emails. It is also recommended to include the unsubscribe link in the header of your email in addition to the footer; this boots your sender reputation.

Unsubscribe Link in the Email Header

HTML Issues

Be sure to avoid using broken HTML or different versions of HTML with plain text. These types of errors cause your emails to be seen as spam and/or phishing attempts. To avoid this, utilize email construction tools that provide clean HTML. Another important note is to not copy text directly from word documents, Excel or Powerpoints, as this will add additional, unwanted characters. Instead, copy your text to a plain text editor that will get rid of the unnecessary characters.

Email Size > 100 KB

A test on email size done by the Email on Acidteam revealed that a file size of 100 KB or less will make your email deliverable, especially toGmail, Yahoo, AOL and Outlook

They created text-only, HTML emails in sizes ranging from 15-650 KB. By utilizing their spam reporting and filters, it was found that a file size between 15-100 KB had no issues with deliverability. 

Email on Acid’s conclusion has been validated, as CheetahMail also conducted a similar test on file size and got identical results.

4. Poor domain reputation

Sender Score

The reputation of your sending domain is crucial in the deliverability of your emails. Your sender score is a number assigned to the domain of which you are sending your emails by ESPs and Internet Service Providers. It is much like a credit score; the higher your sender score, the better your deliverability. Tools like Senderscore.com can help provide insights into the current reputation of your domain.

 How to Avoid Poor Reputation

  • Improve engagement by routinely cleaning up your list to remove inactive subscribers and cater your content to increase open/click-through rates, thus reducing the chances of emails going to spam.
  • Regularly check your sender list as a best practice to enhance email sending quality. Remove anyone who has marked your emails as spam. In addition, remove any invalid email addresses and be sure to only send to users who have strictly opted in.

5. Bad IP reputation

IP Warm-Up 

Warming up your IP is essential in creating great deliverability for your emails. IP warm-up is a process used by ESPs to establish a reputation for a new IP or an IP that has not been used in a long time. 

The warming up process involves sending low volumes of emails and then systematically increasing this volume over a period of time. If ESPs fail to properly warm-up their IPs, it will result in poor deliverability for their emails.

Not Configuring IP Server Properly

Email inbox providers such as Outlook, Gmail andYahoo Mailwill reject your emails if the backend of your ESP is not put together with the proper email header, encryption and authentication parameters.

TLS Authentication

Transport Layer Security (TLS) is a protocol that encrypts emails to ensure that the content cannot be read by anyone other than the intended recipient. You are able to check this by using the email headers upon receipt. It is crucial that your ESPs use TLS authentication for their IPs in order to maintain a good reputation.

6. Failure to authenticate emails

What is email authentication?

Email authentication is the process of you, as the owner of your domain, giving required permissions to a third party ESP, like MAPS. This includes the permission for your ESP to send emails on your domain’s behalf. If you are using an inbox provider like Gmail, Apple Mail, AOL, Apple Mail, etc., your emails will be authenticated by default.

Reasons for Failure

These are a few of the most common reasons for why email authentication fails:

  • Domain age
  • Domain being present in email blacklists
  • Using Via domain
  • Not adding or incorrectly adding DMARC (Domain-based Message Authentication, Reporting and Conformance)
  • Not adding DKIM (DomainKeys Identified Mail) records
  • Not adding SPF (Sender Policy Framework) records

7. Poor email engagement 

Sender list has inactive members

According to a study done by Mailchimp, the average email open rate across all industries is approximately 21.33%. If you fall significantly below this benchmark, spam filters could be triggered to examine your emails. Sending emails to inactive members on your list is not only a waste of time, money and resources, but it also worsens your domain reputation.

It is always recommended to regularly clean out your email list to ensure that all recipients are valid, which is a best practice for avoiding email spam. In addition, SendX, utilized for its capabilities in enhancing email deliverability and preventing emails from being marked as spam, recommends conducting an in-depth cohort analysis to measure user engagement over a specific period of time.

Segmenting your Campaigns

If you target users with many different interests and characteristics, it is best to segment them. This ensures that you are sending only relevant emails, which, in turn, will increase your engagement rate.  

Segments are a combination of “and” and “or” conditions on top of your email lists. Divide your list into various segments based on attributes such as demographics, purchase history/patterns, or behaviors.

Wrapping Up

It is essential to understand the reasons why your emails could be ending up in spam. If this is happening to you, money, time, resources and opportunities are being wasted. Some of your users and potential prospects are not receiving important messages that will draw in more revenue and brand awareness. 

We know that understanding the factors that contribute to why emails end up in spam is extremely complicated. Hopefully this article helps to ease the confusion and allows you to understand the rules and laws of spam. 

MAPS Technologies  complies with all of the laws and rules listed above to prevent emails from being marked as spam. If your emails are ending up in spam or you are struggling with email management, reach out to us for help. MAPS is the all-in-one business management platform that will provide you with the solutions to help your business grow. Maximize your potential with MAPS Technologies.


  1. Charlotte Dawson, Why Are My Emails Going To Spam?, (Clean Email, 2024)
  2. Email Uplers, Boost Deliverability With Optimal Text-To-Image Ratios In Emails, (Mavlers, 2021)
  3. Christina Escovar, Why You Need A Good Text-To-Image Ratio In Email Marketing And How To Achieve It, (Hustler Marketing, 2021)
  4. Harsh P., Why Does Email Go to Spam? Here Are 14 Reasons and How to Avoid Them, (Alore, 2024)
  5. Priya Nain, 7 Reasons Why Your Emails Are Going To Spam (With Solutions), (SendX, 2020)
  6. SendGrid's Email Guide for IP Warm Up, (Twilio)
  7. Dmytro Zaichenko, Email Authentication 101: Everything You Should Know, (AppSumo)
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