What Can Hurt Your Emails From Reaching The Inbox : Email Deliverability

5 Min Read. |

We all have troubles sending our newsletters or promotions to customers through bulk emailing. It happens so often that emails get put into the junk folder or they bounce. What can you do to prevent hurting emails from reaching the inbox / email deliverability? Emails reaching inbox help us get a good sender score.

The sender score is your email deliverability. It measures the reputation of your outgoing mail server’s IP address. Sender score is similar to credit scores, which works as an IP address against other IP addresses. Mail servers will inspect your sender score before deciding what to do with emails. Therefore, a low sender score will hurt the chances of your email reaching your customers’ inbox.

Like your credit score, your sender score can make or break your’s and your company’s reputation. 

What hurts Email Deliverability

There is a process which all emails follow. These are the main components that all email messages always pass through.


A sender puts together the content for the email. Then it is time for the “SMTP conversation” to take place. SMTP stands for Simple Mail Transfer Protocol. This conversation is what makes email messages get from the sender to the recipient. Let’s think of an SMTP conversation as a “handshake”. 

The SMTP server recognizes the domain portion of “xyz.com” and contacts the receiving server responsible for accepting messages for that domain. During this connection, the two servers exchange multiple pieces of information like checking for authentication and so on.  The receiving server typically then decides one of the following:

  • Yes, I know who the ‘person’ is and everything is in order to deliver it to their inbox.
  • I know who the ‘person’ is and all is in order to deliver the message but not to the inbox.
  • Yes, I know who the ‘person’ is but there are still some items I have to identify. (aka a deferred message)
  • No, I do not know who the ‘person’ is and will be sending the message back to the sender. (aka a bounced message)

The factors of delivery depend on the DNS (Domain Name system), Authentication, Reputation, User Level Filtering and Feedback.

So What Accounts For Email Deliverability

Email deliverability is how you measure the success of your emails reaching the inbox without being bounced or marked as spam. If there are issues with bounces, flagging spam filters or low user engagement you may have email deliverability issues.

Factors that may not allow you to deliver:

  • Leaving your subscribers in the dark
  • Sending without custom authentication
  • Settling for single opt-in
  • Sending from a free domain email address
  • Using unclear or spam flagging subject lines
  • Sending emails with too many images
  • Using URL shorteners
  • Making it difficult to unsubscribe
  • Sending to unengaged recipients

Why Do Emails Get Spammed

Spam accounts for 45% of all emails. Have you recognized a spam email at first sight before? If you look closely, you will see unknown email address in the From field, misspelled subject, subject lines written in all caps, large and bold font size and pure promotional. Furthermore, have you ever paid attention to the links you use in your emails? Some links are a cause for email blocking even though they may be from your domain. If your email message contains links from blocked domains, there is a chance to get your email filtered or blocked.

email spam_email-deliverability

Reasons are:

1) Too Many Spam Complaints

Spam complaints will hurt your sender’s reputation and email deliverability in great extent. Your sender’s reputation is the first thing the ISP takes into consideration when filtering the emails. Do not panic if somebody flags your email as spam. Many email marketers receive spam complaints. It’s not a disaster but a sign for you that everything is not fine in your email program. You should address this issue as soon as possible.

2) Too Many Invalid Email Addresses

Repeatedly sending messages to any invalid email addresses defines you as a spammer and leads to email deliverability challenges. 

3) Technical Sending Issues

Some technical issues such as incorrectly formatted message headers, no reverse DNS, PTR records setup or authentication errors will lead to email delivery challenges. Which can also cause the emails being filtered or blocked by ISPs.

There are too many malicious senders like Phishing Senders and Email Spoofing. People have been fooled before. Even though each spam filters differently, they mostly want to know that

  • you are acquainted with ‘person’ receiving the email
  • your IP address
  • coding in your campaign
  • content and formatting – by:
      • Design your campaign to be clear, balanced, and promote engagement from your subscribers.
      • Make sure your subscribers have opted-in to receiving your emails. – by seeking permission.
      • Be consistent. Try not to stray too far from the content and design that your audience already associates with your brand, website, or social media channels.
      • Test by using A/B Testing to compare which content which would promote more user engagement and deliverability.

Also, take care of Firewalls


Firewalls are a lot like spam filters in a way that they are designed to regulate incoming email based on a set of rules that have been established by the email server. Think of them as gatekeepers.

In conclusion, blacklisting is usually the result of bad email marketing or spamming. Spam is any kind of unsolicited email. By sending an email to only to those who have requested to receive it, you are following the accepted Permission-Based email guidelines.

Image credits: www.unlocktheinbox.com, www.artofmanliness.com, Digital Vidya

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