Why Emails Go to Spam Instead of Inbox / 16 Reasons


We’ve all started a new year with lots of wishes, plans and to do lists! Especially for our businesses! I guess we all want to reach our goals and expectations for the best results in 2019.

Email marketing 2019 trends.

While talking about the business, email marketing comes to my mind because it is far more important now than before! 2019 brings a new year in email marketing.

I think it’s great to start with statistics for a better understanding of the importance of email marketing. I believe a successful email strategy is a key point for increasing sales and getting qualified leads.

Active email accounts are expected to hit 5.6 billion by 2019.

  • 86% of business professionals prefer to use email when communicating for business purposes.
  • About 49% of businesses use some form of email automation.
  • Email marketing spending in the United States would grow from 2.07 billion U.S. dollars in 2014 to 3.07 billion U.S. dollars in 2019.

As you can see, email marketing is one of the most engaging methods for growing your business and customer base.

A lot of people still having some trouble with email marketing. Generally, they complain being considered as spam. Thankfully, after reading this article, you’ll understand the main reasons behind that situation!

Hope you find it useful, and if so, please don’t forget to share your experience under the comments below.

Enjoy your time!

How Email Gets Delivered?

How emails get delivered?

Emails reach the destination point from the origination point through the Internet. Of course, this systematic process includes some complex metrics.

This process is significant because our emails are determined as doubtful or trustworthy based on some features.

Junk email illustration.

Most of them blocked on the gateway and never reach the spam folder or inbox folder. That means emails which were passed the gateway have high sender reputation, relevant content and user engagement.

So, let’s discuss some reasons why your emails go to spam folder instead of inbox folder and how to fix this situation with the best practices!

How Do Spam Filters work?

Mailbox providers use inbound and outbound emails to prevent spams but email senders are mostly concerned with inbound filters.

Spam filters have some metrics and algorithms to filter emails. After the filtering process, there assigns a numerical score that represents the probability of the message being spam.

Gateway Filters

Large businesses and organizations use Gateway email filters like Barracuda and Mimecast to decide whether to allow the email to go further or not.

Hosted Filters

Hosted Filters like Cloudmark and MessageLabs are used in companies which have elaborated their own method to detect spams based on sender reputation metrics and content.

Desktop Filters

Desktop Filters are the tough ones to get through because they are configured by the user. Outlook with the SmartScreen anti-spam filter from Microsoft can be given an example.

You have Low Sender Score

Sender Score is an algorithm that ranks every outgoing mail server’s IP address. It is related to the reputation of the sending IP and sending domain.

It shows your sender reputation on a scale of 0 – 100.

Email marketing sender score.

Some email metrics determine the Sender Score such as unsubscribes or spam reports. If you wonder your Sender Score, go to Return Path’s registration page.

So having a low sender score cause a rejection by ISPs. Accordingly, your emails won’t reach inbox folder.

IP Address

An IP address is a number listed in the domain name system that is used to send email messages on behalf of your domain name. Marketers can use dedicated or shared IP addresses to send emails.

It may be dedicated to a specific sender or used by multiple senders to deliver emails.

Maybe you’ve just gotten a new IP address and didn’t warm it up enough! If so, then you should definitely do that before sending too many emails!

Building a reputation is necessary for the quality of your IP! Also, after building a reputation, I recommend maintaining consistent volume levels. Apparently, Mailbox providers tend to filter emails out if they observe spikes.

Wondering your reputation? Check Sender Score tool and find out more.

Sender score Return Path example.

Also if you’re sending from multiple IP addresses, this is a big mistake!


A domain name is a registered name on the Internet and it consists of domain authentication and domain reputation.

Domain Authentication

It allows the receiving server to confirm the sender’s identity. Authentication is very important to secure your brand and build a good reputation.

There are three primary methods of authentication:

  1. SPF (Sender Policy Framework): it validates that a message is sent from an IP address that was authorized to send messages on the behalf of the indicated sending domain.
  2. DKIM (DomainKeys Identified Mail): it authenticates an email using public key encryption. It signs a message in a way that is difficult to forge, proving that the message is sent from the indicated sending domain.
  3. DMARC (Domain-based Message Authentication, Reporting, and Conformance): it ensures that an email is properly authenticated against established DKIM and SPF standards and that any fraudulent activity that may be coming from legitimate domains is blocked.

(Source: Glockapps)

You can check your authentication records with the GlockApps spam testing tool.

Authentication test for email marketing.

You have Spam Complaints

You should listen to your audience. For example, if your subscriber can’t get out of your list immediately she can mark your email as spam.

In this case, domain reputation is very important.

Domain Reputation

To make the filtering decisions about where the email should go, mailbox providers look at the metric called a domain reputation.

Domain reputation is dependent on:

  • Inbox placement rate
  • Spam placement rate
  • Complaint rate
  • “This is not spam” rate
  • Hard bounce rate

But the worst scenario is the spam complaints because it represents your unwanted emails. So, experts say that the ideal complaint rates should be below 0.1%. A complaint rate higher than 0.1% puts a red flag for the sender and will lead to the email rejections or blocks if the issue is not fixed.

You weren’t Given Your Customer’s Permission

Customer permission in email marketing.

Take your customer’s permission if you didn’t yet. This is the golden rule of email marketing. Believe me, people don’t interested in your special discounts or products if they don’t know you.

If you’re sending emails randomly, you should know that it is unethical and ineffective. There are lots of marketers and business owners that buying an email list, which is a total mistake!

There is nothing you can benefit from an email list which is bought from somewhere else. You should create a target audience and do your best to convert them into your loyal customers.

So, you should add someone’s email address if s/he only willingly opts-in to your list.

You Didn’t have a Strategic Schedule

Make a schedule for your emails.

Another reason for you to be considered as spam is you might not have an appropriate schedule for your emails. If this is the case for you, please start making one!

Try not to send e-mails to your customers at inconvenient times. Also, as you get to know your audience taste, you can set an email sending frequency.

If they prefer to get an email from you once a week, you should make it happen.

78% of consumers unsubscribe from emails because brands were sending too many emails. Make your offerings easy for people to take advantage of otherwise you may not be as successful as you want. Your IP Address Flagged as Spam

You don’t have to send spam to be considered as a spammer. If your IP address was flagged as spam then there is a big problem in terms of your reputation.

Also, an email service provider is an important metric. For example, you may use MailerLite to send your campaigns. That means, your emails are sending through their servers. So, if someone sends spam through their service, your reputation and deliverability can be affected as well.

My advice is to use a reputable email service provider because they prevent these scenarios with strict procedures and regulations.

You have Low Open Rates

Increase email open rate in email marketing.

If you have low open rates, your emails are at higher risk of being flagged as spam.

Remember the first condition of email open rate:

The reader allows images in the email to be displayed in the full view of the email or preview pane.

and the second condition is,

The reader clicks a link in the email.

Open rates are calculated by email service providers. ESPs consider the number of people who open the email and dividing it by the number of emails sent that failed to reach the reader.

For example, if you sent out 100 emails, 20 bounced, and 10 were opened, you would have an open rate of 12.5%.

According to MailChimp, the average email open rate of all industries is 20.81%.

You should,

  • Use Engaging Language
  • Pick the Right Time
  • Keep Your Email List Fresh
  • Segment Your Email List

Your Email list is not Fresh

Email list cleaning is something you should definitely do for a high-quality email list. If you don’t do that regularly, maybe this is the reason for your situation!

You should update your email list and remove inactive subscribers who have not engaged in the past 6 months or more. Also, you should give it a try to re-engage them. Ask them if they’d like to update their preferences and information. This way, you can eliminate your list. By eliminating the bad data, you’ll be what you need, eventually.

If you need some advice on some email list cleaning service, click the link below:


In order to avoid spam complaints, you should use a double opt-in form. This way, you can collect the real data and provide your value to people who want them!

Also, don’t forget to send a confirmation email to the new subscriber in order to prove their address and build the agreement.

You have Inaccurate Sender Information

If you don’t provide accurate information about your routing information as well the domain name and email address, this might be the reason!

You should identify yourself, your business with accurate sender information.

There is no Appropriate Physical Location Address

According to the Federal Trade Commission (FTC), including a valid, physical postal address is necessary. Companies and marketers should be transparent and traceable.

In this case, you should include your street address, a post office box you’ve registered with the U.S. Postal Service, or a private mailbox you’ve registered with a commercial mail receiving agency established under Postal Service regulations.

Your Subject Line is not Effective

You have a Spammy Subject Line

35% of email recipients open email based on the subject line alone. Don’t use more than 50 characters in your subject lines. Also creating a compelling and eye-catching subject line will be helpful to increase email open rates. Don’t forget to trigger your customers with an immediate call to action.

Also, you may generate curiosity with compelling questions and personalized email subject lines! Finally, don’t forget to A/B test your email subject lines to understand which one best fits your business & audience!

Email subject line example.

For detailed information about email subject lines, please check the link below:

There are Spammy Words

Email marketing spammy words.

If you’re ending up in a subscriber’s spam folder, maybe that’s the reason! Most of the ESPs have identified some common words in spam email. You can check spam trigger words based on your industry and avoid using them! Here you can find a detailed spammy word list, check it out for details.

The Ultimate List of Email SPAM Trigger Words

You have Spelling Issues & Grammatical Errors

Grammar mistakes and spelling errors in spam emails.

There are a lot of spammers who are not an English native speaker. So, when you analyze their email, you see that there are various grammatical errors with a strange structure.

In order to block that kind of emails, spam filters detect those structures. Also, when you consider that email marketing is something serious, you should be careful with your tone and spelling.

Most importantly, in B2B communication, it is essential to look professional in the eyes of your audience.

In this case, I recommend you to use Grammarly, but for the best results, you should open your eyes carefully and check your email 2-3 times!

Another reason:

maybe your segmented audience prefer to get emails in HTML format and your emails didn’t follow the best practices!

In this case, you should

  • Make sure that your HTML code is simple and clean. Stay away from the complexity.
  • Never send image-only emails with no text and of course, compress them for the ideal size.
  • Use fonts that work across platforms, unknown fonts don’t work in everywhere.
  • Make sure that your emails are mobile responsive.

So, in this article, I tried to tackle some common reasons and practical solutions for your email marketing benefits!

Remember, the golden rule in email marketing is to make people open your email. That is why you need to reach the inbox and pass the spam filters.

If you share some techniques you have used to prevent this situation, I’d be appreciated!

Thank you for your time!


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