News and tips from the industry leaders in email compliance.

This is a guest post, written by Jenna Divinney of Webbula.

What causes poor deliverability?

Unfortunately, there isn’t just one single answer and more often than not, it’s caused by the person and/or team sending emails. This isn’t to point the finger, but it really does boil down to following email best practices. Say, for example, you’re learning how to hit a baseball, and you strikeout every time. Your coach (the expert) suggests a different way to hold the bat, change your feet positioning, or even swing two seconds later than you’re used to. 

Your end goal is to execute, make contact, and see it soar through the air and land in the stands. In this case, the glove of the fan in the stands is your subscriber’s inbox, and the glove of the opposite team is the spam folder. The difference between striking out and hitting a grand slam is simply a few tweaks. 

As stated before, the cause of poor deliverability is not singular. There are a multitude of factors that make up deliverability and they are all connected and intertwined to make up the bigger picture result of causing poor deliverability. A few examples of things that cause poor email deliverability are (but not limited to):

  • Spam complaints

Brands look forward to customer feedback, but not this type of feedback. A few reasons you could be getting spam complaints are:

  •  the recipients aren’t properly opted in, 
  • you don’t have an unsubscribe button in your emails or it’s too hard to find
  •  you’re sending too many emails
  •  the email content has significantly changed since they opted in 
  • or subscribers simply do not want your email anymore.
  • Email volume 

Mailbox providers are extra cautious when they see brands sending a high volume of email. The key is to have a consistent sending pattern. It’s common for spammers to send a large amount of email randomly and inbox providers look for that sudden high volume pattern. 

If you want to send more email, it’s a best practice to slowly ramp up your volume over a few weeks as you head into higher email frequency times of the year, and give your subscribers the option to control their preferred frequency. 

  • Not having proper email authentication set up

There are three email authentication factors that ISPs look for: SPF, DKIM, and DMARC, with SPF and DKIM being the most common. To find out if you have proper email authentication, check your email header for “PASS” or “FAIL” next to the authentication name. 

  • SPF – (Sender Policy Framework)
  • DKIM – (Domain Keys Identified Mail)
  • DMARC – (Domain-based Message Authentication, Reporting and Conformance)

Let’s not forget about the newest, BIMI, that enables email inboxes to display your brand logo next to the email message to give subscribers a visual confirmation that you are a trusted sender.

  • Email engagement metrics 

Mailbox providers also pay attention to the positive actions that come from your subscribers like how often they are clicking through and taking action. This also means that it is imperative to keep an eye on those subscribers who aren’t taking positive actions, and regularly evaluate how often you are sending to them and the types of content that might appeal to them more. Invest time in learning how to personalize your emails to each subscriber’s wants and needs as often as possible.

  • Purchasing lists — a good email list is never for sale

When purchasing an email list, it’s very unlikely that the list is 1) your target audience, and 2) has legitimate email addresses. Purchasing a list comes with many consequences. 

How do you know if there are problem accounts—such as spam traps, honeypots, bots, seeded trackers, and disposable domains—in this list? Are you even aware of these threats? If you hit any of these problem emails, it could significantly damage your sender reputation and send you right to a blocklist, permanently stopping you from sending. So why take the chance?

The other issue with purchasing lists is that most ESPs won’t let you send to them. If you are using email marketing software to send your emails, you will see that all reputable ESPs insist that you use an opt-in strategy to build your email data from the ground up.

And that’s not only for enterprise marketing automation tools either. Even in the smaller self-service market, this is true. In many cases, when you upload a list, the emails are automatically checked by the ESP or a security partner to prohibit brands from destroying the ESPs sender reputation. 

If it detects malicious emails or a clear violation of their opt-in policy, you’ll automatically receive an incident report, and your account may be frozen or blocked from sending permanently. So don’t try to pull a fast one no matter how tempting it may be— stay away from buying lists. 

  • Poor list hygiene 

​​List hygiene is just one facet of email deliverability, but it is so extremely important to obtaining and keeping good deliverability and sender domain reputation. It’s easy to go down a rabbit hole when it comes to list hygiene and segmentation. 

Questions you should ask yourself when it comes to lists are:

  •  “Did this person choose to receive emails from me?” or,
  •  “Are my emails relevant to the sender to whom I am sending emails to?” 

However, even good subscriber data expires at some point. People change jobs, retire email addresses, etc., and it is the brand’s responsibility to keep up with their list hygiene to remove dormant or malicious emails from their list on a regular basis.

How to improve email deliverability 

  • Authenticate your domain

You need to be a trusted sender when you’re in the email marketing world. Authenticating your email will put you on the ISP’s good side and show them you are a good sender. Without authentication, you could also fall victim to email spoofing. 

  • Choose a reputable provider

Choosing a reputable ESP can feel like shopping for a car. Not only are you concerned about your budget, sending volume, and included features, but how will the ESP help you maintain a good reputation with the ISPs you send to?

Does the ESP offer white-labeled authentication, feedback loop registrations, subdomains, reverse DNS? Does the ESP offer assistance with legal compliance, do they automatically suppress unsubscribes, hard bounces, and misspelled domains? There is a lot to consider when choosing a reputable provider. 

  • Make email preferences clear and make it easy to unsubscribe 

Make it clear to subscribers what emails they are receiving, and make it easy for them to opt in and out of certain messaging. It promotes transparency that your subscribers want and appreciate and also reduces total unsubscribes if they have the option to only opt-out of promotional messages but stay on the newsletter, etc.

  1. Maintain proper IP allocation

As your email program starts to grow, you’ll need to adapt and prepare for an appropriate email infrastructure by sending on a dedicated IP address. With a dedicated IP address, there needs to be a proper IP warming strategy. Yanna-Torry Aspraki, and Sergey Syerkin recently wrote a great article about IP Warming basics: Shared or Dedicated 

  • Choose double opt-in

Protecting your deliverability starts with protecting your front door: your web forms. Using double opt-in is a great solution because once a customer signs up for your emails, they will receive a confirmation link to continue the sign-up process. This is one step to verifying that there is a real person on the other end of your form submission, but it’s not totally foolproof.

The best way to ensure you catch bots before they enter your forms is by implementing a lead validation service that integrates with your CRM, email service provider, or lead capture forms to ensure the best top-of-the-funnel-data quality leads are entering your lists.

  • Segment your lists 

Segmenting your lists and focusing on the unengaged is very important. As mentioned above, ISPs look for that positive feedback, and if your subscribers aren’t interacting with your emails, that could ding your deliverability. 

We wouldn’t recommend to stop sending to unengaged subscribers right away, but try sending to them less frequently, or switch up the type of content. Most importantly, test! When you see more interaction from people on your unengaged list, then move them to your active list. 

  • Send engaging and personalized content

Go beyond the first name personalization. Get creative with your offers, and find out what your subscribers want to see from you. Otherwise, there will be less opens, less clicks, less conversions, ultimately resulting in poor deliverability. 

  • Secure web forms with real-time verification

A real-time email cleansing API is designed to quickly determine if the email being submitted is a valid working email address and not a bot. This will help decrease the fraudulent or inaccurate data submitting into your forms, protect your deliverability and sender reputation, and improve your campaign ROI. On the front end, it will also create a better experience for your customers, catching common typos like before they’re submitted.

  • Regularly clean email lists with email hygiene

Apple preloading tracking pixels (the way that email opens have historically been recorded)  validates that email hygiene is no longer a ‘nice to have’ but an absolute necessity. Marketers who have relied heavily on email open rates should take note. Depending on ‘opens’ as an indicator of quality is no longer an option. 

Marketers need an additional layer of intelligence to mitigate the risk of blindly mailing to potential threats, and that is something that Webbula’s Email Hygiene was specifically built for. Brands need to protect their online web forms from malicious sign-ups before they enter your CRM/Database and periodically run Email Hygiene to identify aging and potentially harmful addresses like spam traps, fraudsters, and disposable domains from damaging a brand’s reputation and mailing resources.

COVID-19 has also caused a surge in bad emails. People lost their jobs, which meant a lot of emails were abandoned. Sending these emails could cause a change in your deliverability. Cleansing your list before big sends and at least quarterly is always a best practice.

Visit Webbula’s blog to read Part 2

About the Author 

Jenna Devinney is the Content Marketing Manager at Webbula. She manages social media, creates eye-catching content, and oversees web design. She’s a jill of all trades writing a surplus of 100+ blog articles over three years in the email hygiene and data solutions space.

Webbula is the undisputed industry leader in Email Hygiene, Data Enrichment and Audience Targeting services. Check out to see what Webbula has to offer.

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