Deliverability: Common issues and Best advices

Email deliverability plays an important role in the success of your email campaign. In this article, we will explain everything you need to know about email deliverability and how you can make sure that your emails can reach your audience’s inbox.

I/ What is email deliverability?

Email deliverability is when an email is successfully delivered to the recipient’s inbox . This is not to be confused with email delivery, which actually means that an email has been sent successfully to the recipient ‘s server.

II/ What influences email deliverability?

1. Sender identification

This describes a series of protocols that show you who you are when you send emails, such as the SPF (Sender Policy Framework), DKIM (DomainKeys Identified Mail ), and DMARC (Domain-Based Message Authentication, Reporting, and Conformance). Any of these systems acts as a passport, license or background check

2. Sender reputation

Whenever you send email promotions, mailbox providers conduct credibility tests. Senders with an outstanding reputation will have their messages sent to recipients’ inboxes, whereas those with a bad reputation will land in the spam folder, or even be rejected at the gateway.

Your sender’s credibility is a ranking that shows how trustworthy your emails are. Every company and Internet Service Provider ( ISP) have different ways to score for you, but attracting positive actions from subscribers (which means subscribers refer to you as a trustworthy sender) is the best way to improve sender reputation.

3. Infrastructure

Email infrastructure is a system built to process the delivery of all newsletters or transactional emails you send to your subscribers. While there are other components, email infrastructure is typically represented mainly by IP addresses.

III/ Common issues with email deliverability

1. Negative Sender Reputation

Reputation of the sender is an indicator of the reliability of the IP address and domain of the sender. Mailbox providers take into account different metrics to assess the sender ‘s credibility, including spam complaints, mailing to unknown customers, industry blacklists, and more.

2. High Complaint Rates

The trick to email marketing is to ensure that you send relevant emails to people who want to receive them. If you don’t, then you’re opening up for a subscriber’s complaint. And the more complaints you get, the worse your email deliverability is going to be. Holding the subscriber complaint rate low is key to maintaining a good sender reputation and high deliverability rates.

3. Getting Listed on a Blacklist

A blacklist is a list of IP addresses or/and domains that have been identified as “known” spam sources. They are open to the public and exist to help mailbox providers protect their users from unwanted emails. If your practices or content appear to be spammy, you will end up getting blacklisted, regardless of whether or not you are a legitimate, permission-based sender.

4. Poor List Quality

Maintaining a high-quality list of subscribers is crucial to ensure that your emails are sent to the inbox rather than the junk or spam folder. In addition to receiver complaints, there are three other big guilty parties of bad list quality: spam traps, unknown emails and invalid emails.
- Spam traps are email addresses that do not belong to active users and are used to classify spammers and senders with poor email acquisition practices.
- An unknown email is one that has never existed, has been terminated by the email service provider, or has been abandoned by its last owner.
- Inactive emails are customers in your list file who have not opened, clicked, or taken some kind of action for a considerable period of time.

5. Lack of Email Authentication

Authentication enables the sender’s identity to be checked by the recipient of the email and the mailbox provider. If the sender’s identity can not be authenticated, mailbox providers will reject the message or use additional filters to decide whether it should be delivered.

IV/ How to Improve Email Deliverability

1. Keep a clean email list

A large number of inactive subscribers can have a dramatic effect on your ability to perform because they hurt your engagement metrics. Consider deleting or suppressing inactive customers, including spam traps after a specified period of time or automating a re-engagement campaign.

2. Provide easy unsubscribe options

It’s a common misconception that unsubscribing is a bad sign, but there’s no proof to show that unsubscribing rates impact deliverability. Actually, it will help if you improve your subscriber interaction and clean up your email list

Sending targeted campaigns to people who truly want to receive your emails will help increase opens and clicks and reduce bounce rates. But, if users want to unsubscribe, make it easy for them to do so. Make the unsubscribe process quick in just one step — otherwise, you’re going to have a losing battle against the hurtful “report as spam” flag

3. Create Engaging Content

Make your emails personal
Email is one of the most personal platforms when it comes to marketing. Sending emails that connect with your audience and leveraging the one-to-one communication nature of the medium will not only have a positive impact on your deliverability — it will also improve reader interaction and create stronger relationships with your audience.

Practice good text-to-image ratio
Sending an email that only contains images is a sure-fire way to have delivery issues. You should take the time to create an email with text and images - not just a single image. On the flip side, it is not necessarily better to send plain text emails.

Some spam filters check text-to-image ratio and it's essential to keep it a healthy one. The general rule is to have a good, balanced mix of text and images. Providing 2 to 4 sentences per image helps give context to the ESP and your recipients.

Avoid spammy content
Some spam filters don't like the way email content is being phrased. Take a look at some common mistakes that you should avoid:
- Excessive use of exclamation points (!!!!!)
- Using some phrases like "Once in a lifetime opportunity!" or "Click here!"
- USING ALL CAPS IN EMAIL SUBJECT LINE AND IN BODY TEXT. This makes recipients feel like you're shouting at them!
- Hash-busting: Inserting random characters in your email subject line or content to fool spam filters (i.e., "F.ree p.r!z.e")
- Be aware of words associated with the language of sales. Of course, you can still use them, but don't use them too often. If overused, they may trigger spam filters and then route your emails to junk folders. Several risky words include "free," "prize," "bonus," etc.

4. Whitelisting

Whitelisting is simply adding an email to your list of contacts. You can ask subscribers to whitelist you, which will help boost email deliverability

The ideal way to get a whitelist is to create a workflow in your email campaign. It can be like this: “You’re getting this email because you’ve opted in via our website. Make sure you keep these emails coming by whitelisting us!” Remember, the request to be whitelisted is a big favour, so make sure you reserve it only for your most potential subscribers.

5. Consider email frequency

To boost email deliverability, it’s best to avoid irritating your subscribers by sending too many emails too frequently. Although data points to the ideal send frequency once every two weeks, it is by no means a science. So to decide the perfect email cadence, which is the timing and types of emails you should send to your subscribers, you can try out the following tips:
Know who the audience is and appreciate their buying journey.
Survey your audience to understand how to segment your list based on their preferences.
Set up frequency preferences and let your audience choose theirs.

6. Warm-up your domain

Also known as IP or reputation warming, this is a way to boost your reputation profile when you just get started. Ideally, the list should be small and active at the beginning.
The reason is that engagement, such as opens, clicks, and responses, are all a good sign of credibility – so a smaller list of more engaged recipients will give you a greater ratio of active, interested parties.

If you kick things off with a 10,000 blast of email to people who have never heard of you, your deliverability is going to be bad, and you’re going to risk ruining your reputation. Instead, take the list of 10,000 contacts and break it down.
Week 1: emailing to 250 recipients
Week 2: emailing to 500 recipients
Week 3: emailing to 750 recipients
Week 4: emailing to 1300 recipients, and so on.

Final Words

That’s it! I hope that this article has provided you with valuable information about email deliverability. Please feel free to contact our support team via if you have any quesiton.

Updated on: 19/10/2021

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