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Email Deliverability Issues

How to increase email deliverability


Have you realised your metrics on email engagement have significantly dropped? Or emails bounce or even end up in the spam folder! It is possible that you have some issues with your email deliverability. It’s a common challenge marketers have to address as they implement their strategies on email marketing. Statistics indicate 1 in every 5 emails do not reach the intended inbox. Email deliverability issues could become significant in the performance of your overall campaign. Email deliverability refers to the ability to deliver emails to the recipient’s inboxes. The metric is often complex, depending on several elements for example sender’s domain, service provider, the quality of email list, IP reputation, email frequency, and the overall senders profile reputation. Key to note is that email deliverability should not be confused with delivery rate. Essentially, delivery rate means the percentage of emails received by the subscribers’ mailboxes irrespective of whether they land in spam folder. On the other hand, deliverability indicates the inbox placing indicator. It shows you whether emails get into the subscribers primary inbox. Thus, even with a sound delivery rate, you could still experience issues with email deliverability.

Email Deliverability

A good email deliverability rate is difficult to define. Statistics show 79% of commercial emails reach the inbox. The rest is sent either to spam folder or goes missing. Every marketer’s goal is to achieve 100% email delivery to subscribers. However, this high rate of delivery is hard to attain. Pay attention to some of this metrics as you track your email deliverability:

  • 95% and higher is a good email delivery rate.
  • Bounce rate, both hard and soft bounce should not be higher than 3%.
  • You need not ring spam bells if spam rate does not exceed 0.08%.

Ideally, your email deliverability is depended on the platform you used when sending emails. Different service providers have different rates of delivery. Quite often, the fluctuation is between 88-99%. If you follow the best practices and begin to send email campaigns by first warming up the reputation of the sender, you can achieve deliverability closer to perfection.

The reputation profile of the sender plays a significant role in email deliverability. For this reason, you need to know what it is and in what circumstances you need to implement reputation building processes particularly into your strategy.  

What it means by sender’s reputation warmup?

This is the process through which you improve your reputation profile in order to avoid spam folder. It can be achieved if you gradually increase the emails you have been sending out based on a particular schedule. Reputation warmup is recommended highly when your subscriber email list is in excess of 50,000 contacts.

The procedure is done when:

  • You move from one email marketing service to the other, effectively gaining new and dedicated IP address.
  • You have just started email marketing.

It would be more effective if the subscribers you engage in the first few rounds are active. This means they are likely to click and open your emails, thereby sending a good signal to Outlook, Gmail, and Yahoo among other providers indicating your content is of quality and your IP address in trusted.

Email Deliverability Issues

  1. A high complaint rate

If an email is no wanted, it will be marked as spam. It’s one of the major factors that lower the reputation of senders. For this reason, your emails may begin landing in spam folder. Hence, you need to avoid spam complaints if you can.

  • A high bounce rate

This means your list is of low quality, outdated, or has purchased email addresses. As such, inbox providers would treat you poorly, consequently affecting your reputation.

  • Low engagement

Imagine a situation where a subscriber receives 50 emails but fails to open any of them. It’s a signal to the inbox provider that a sender has not followed the best practices. More of their emails will land in spam folder. You need to check how such email addresses were first collected. Bid ‘goodbye’ to the inactive contacts rather than wait for them to unsubscribe. It’s possible for a smaller and active email list of 10,000 contacts to drive more sales compared to 50,000 since 40,000 of them are inactive and the bad contacts are damaging the sender reputation. Again, sending emails to contacts who remain inactive is not cost-effective.

  • Too frequent campaigns

Receiving too many campaigns a day might overwhelm even the best and high-quality subscribers. They will mark your emails as spam while others will unsubscribe from your emails. The most recommended and ideal frequency is 2 or 3 times per week and for daily senders, it should not be more than once in a day.

  • A sudden increase in the number of emails sent

If you initially used to send to 50,000 subscribers then you suddenly increase the number to 150,000, the spike would cause your emails to be sent to spam folder. Mostly, inbox providers consider spikes as unexpected behaviour or even spam attack. Therefore, you should increase the size of your mailing list gradually.

  • Constant switch between different email service providers

This constant switch hurts your sender reputation considering the inbox provider starts viewing you as another spammer trying to hide his or her trail.


There are several measures you can take to ensure your email deliverability is at a good level. First, you should use SPF and DKIM in order to ensure email providers are better placed to verify that messages emanate from you. This keeps your deliverability at a good base level in the very minimum. Additionally, only send emails to contacts eager to hear from you. This means a proper management of the list is key. You can achieve this by cleaning your lists on a regular schedule, after every 6-12 months. The content in your email should always match the expectations of your recipients. This should include the content that would push them to decide they need to open your email or not-the subject line. A subject line is very important because in 7-9 words you should have convinced your recipient that your email is worth opening. However, it should go beyond that since certain keywords used in the subject line might land your email in spam folder. Again, this hurts your click rates, open rates and the entire campaign. Hence, a good subject line equals good open rates, effectively improving your deliverability and results of the overall campaign.

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