Minor Yet Important Issues That Affect 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.

For example, if the “From” email address is “support@” 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.

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.

3. Email Content

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.

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.

4. Email Blast 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.