How to Fix Poor Email Deliverability

In addition to some technical problems that may cause your emails being blocked or filtered, there are other issues that can negatively affect your deliverability. The issues we’re going to examine are related your email copy and are under your full control. That makes it more important that you carefully check your email newsletter before sending it to the whole list in order to get a higher delivery rate.

Here is what you need to pay a closer attention to when creating and sending your email newsletter:

#1: Email Header

The email header is just like your business card. When you send an email, your email server enters into conversation with the recipient’s email server. Your server sends the message header to the recipient’s mail server. If the recipient’s server does not like how your header looks, it will not accept your email.

When sending bulk emails, it’s easy to change the “From” email address, but it’s not so easy to mask the sender’s mail server identity. So, spam filters look at the domain name rather than the “From” email address. In particular, filters make sure that the “From” email address is from the same domain that is sending the message.

For example, if the “From” email address is “” but the email server from which the message is sent is “” then the server supposes that the email header is forged.

Falsified email headers can be a big concern since some ISPs (in particular, AOL) stated that they will delete the emails with falsified headers and will prosecute malicious senders.

But there are situations when you may inadvertently falsify your email header without even realizing it:

1. Your email header will look like as falsified if you use an ESP to send the emails but type your own emails address into the “From” field rather than using a “From” address originating from the third party’s email server.

That is why it’s important that you make sure that your “From” email address is one that is hosted on their mail server. Contact the ESP and ask them if the email address you use as the “From” email is assigned to their list host server.

As your “From” name, you can use your own name or your organization name. And you need to provide your own email address as the Reply-to address because the replies will go to the Reply-to email.

Bounced emails will be directed at your Return email if you setup one. If you don’t have a separate email account for bounced messages, they will be reported to your “From” address.

Here is how the message header is formed if you send the emails with our email newsletter software EasyMail7.

email message header

2. If you have a “forward-to-a-friend” feature on your site or email messages, and the email address from which the message is forwarded is used as the “From” address, this would be a case of a falsified header.

Instead of forwarding the message from the original recipient’s email address, forward it from an address on your email server. Just make sure you use the friend’s name in the subject line of the message and the friend’s email in the Reply-to address.

#2. HTML Code

There is nothing wrong with sending the message in the HTML format. But a wrong HTML code is a very common reason for the email to be filtered. Even very simple errors in HTML can get you into trouble with the filters. HTML emails can be blocked by spam filters because:

  • No plain text version was included, so the recipient has to read HTML
  • No alternate text was added for graphics
  • HTML code was slipshod or incorrectly formatted
  • HTML code contained dead links
  • HTML code contained scripts that an ISP may consider harmful

To make sure your email won’t be filtered because of the wrong HTML code, use HTML validator tools to check your HTML email before you send it out. If your list contains big portions of email addresses from specific ISPs, you can check with those ISPs if they have any requirements for HTML. For example, you can read how a HTML email must be coded for AOL here

To help you design a HTML email, fill in the form below the article and get a free “Coding HTML Email” report via email. In this report you will find best HTML email coding practices for different email applications.

Plus, you can download free premium HTML email templates and use them to create your email newsletters.

#3. Email Content

Although an email sender reputation has become the most important factor that determines the email delivery success, you still need to be careful with the email copy you send and not “overdo” it.

ISPs usually rely on a combination of factors to decide if an email should be delivered or filtered, and the message copy is one of the variables that affects deliverability. Copy is even more important if the ISP uses heuristics as a filtering criterion. There are words and phrases that increase the email score which is not good. The higher score of the message, the more it looks like spam.

Here is a list of most common words and phrases that trigger anti-spam filters.

You might not use many of those words and phrases in your emails but have you ever begun your email with “Dear Friend”? Or you have ever put a subject line beginning with “For just $10…” or the like? Or probably you included your “special promotion”, “free consultation” or “money back guarantee”? Any of these phrases would grow your score.

From the other side, you can rarely do without making any discounts, special offers, and other types of promotions in order to urge your recipients on acting upon your email. So, you often have to use so attractive for the recipient spam looking words.

Just remember that email copy does contribute to your deliverability rate and choose words wisely. A single word or phrase from the spam triggers is not likely to cause your email to be filtered while other elements in your message don’t increase your score.

It’s a great idea prior to sending the email to your list, run the email copy through a spam filter with a checker tool like GlockApps. The test will show you what elements in your email can generate negative points.

#4. Email Volume and Speed

This factor doesn’t relate to the email copy but we think it’s important as well. Spammers don’t care about email volume, speed of sending, or list hygiene. Some ISPs watch closely at the sender who is trying to send a large volume of emails with them. In case of any problems such as a high number of undeliverable emails, or spam complaints, the account is shut down by the ISP.

Ideally, you should respect each individual ISP’s requirements. Some ISPs do allow you send all your 100,000 emails at once; others will limit the quantity of emails you can send at a time or per hour/day. In EasyMail7 you can send the email throttling per hour and/or per day according to your ISP restrictions. .

How to Test Your Inbox Delivery Before Sending Real Email Campaign

You can use the G-Lock Apps delivery and spam testing tools to test your Inbox placement, spam scores, authentication issues, daily blacklist monitoring to check if your server’s IP address is blacklisted and get summary email alerts if any problems are detected.

The G-Lock Apps delivery report presents:

sender authentication test: DKIM and SPF;

spam filters tests;

message placement at different providers: Inbox, Spam, Newsletters or x if your email was blocked and did not reach the mailbox. At Gmail the report will show if your email was delivered to the Primary, Social or Promotions tab.

delivery duration;

full header of the received message.

The primary reason why you'll want to run an Inbox placement test is to verify that your email newsletters are reaching the recipient and not marked as spam or blocked. The Inbox placement test is a great opportunity to investigate how your message is treated by major email providers and solve deliverability problems in advance.

You may be thinking that you are sending great campaigns but in reality it may be the opposite. If one day you find out that your email open rate is much lower than it is used to be, or you get complaints from your subscribers that they are not receiving your emails, it's a sign that something is wrong with your email program. This is when you should take an extra step and send a delivery test. If any issues are revealed, take time to fix them before your next campaign.

A regular testing of the Inbox placement allows you to monitor your sender reputation with different email service providers and make sure that you are in good standing with top domains on your list.

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Comments (1)

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    Some really good tips here – I find that getting the subject is so key to my email marketing campaigns. They say that ‘the first bite is with the eye’ when it comes to food and it’s the same with email.

    we all know a spam email straight away so it really pays to put some thought into your subject header. make it personal, warm or funny. If you’ve spent that long getting the content of the mail just right you should put a similar amount of time in making sure that people read it!

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