How to Repair Your Email Sender Reputation

Zameer RazackGeneral

Good Practice Email Marketing

Executive Summary

Good Practice Email Marketing
Email service providers, such as Gmail, Outlook, or Yahoo Mail, determine whether email marketing is malicious or bothersome by understanding whether the sender shows effortful behavior in having good customer relationships.

Rules and Guidelines for Emailing your Customers
These email service providers only place emails in the customer’s inbox that come from senders they consider legitimate. The key markers of a legitimate sender are: using a well-maintained mailing list without non-existing emails, sending newsletters that are interesting to the customer, not sending emails to customers that are unengaged, sending emails using an authenticated domain name.

Attaining a High Domain Reputation Score
Compliance with these rules and guidelines will lead to a high domain reputation score. Exponea allows you to analyze the customer behavior around the incoming newsletters and choose the best moments for each of your customers to receive these emails.


One of our fashion e-commerce clients operates a marketing strategy that focuses on maintaining customer relationships by sending personalized recommendation emails. This strategy aims to increase the frequency of purchases that their customers make.

Their original email marketing operation left our client with a bad domain reputation score among all the email service providers. This caused a halt to their marketing operation because their customers no longer received any emails.

Our consultants were called in to evaluate our client’s email marketing practice and make their operation compliant with the rules and guidelines for good practice email marketing.

Why does it matter?

Good practice email marketing is not about merely making peace with the requirements set by the email service providers when reaching out to your customers. It’s about the contribution of your business in ensuring that customers of all ages and walks of life can take part in a safe and secure internet.

A flourishing internet e-commerce ecosystem depends on the customer’s trust in the ability of online stores to communicate and execute financial transactions securely and reliably.  Unfortunately, cybercriminals are keen to discover and exploit weaknesses in the security of online stores. Their most common strategy is to hijack one or more communications channels of an online store and scam its customers into thinking that they’re sending their credit card details to a genuine business.  

In the least malicious scenario, the financial transaction would result in the customer receiving a counterfeit version of the product the customer intended to order. In the worst case scenario, obtained personal details would be used for theft or other fraudulent uses, such as submitting false medical insurance claims.

It is therefore in the interest of e-commerce businesses to ensure that they are compliant with the practices that guarantee the authenticity of the online store’s communication channels.

How Email Service Providers Score Your Domain Reputation

Email service providers, such as Gmail, Outlook, or Yahoo Mail employ highly diligent evaluation methods to determine the reputation of a sender. The resulting reputation score determines whether an email appears in the inbox or the spam folder. Their principle reputation scoring guideline is whether the sender shows effortful behavior in having good customer relationships and whether the receiver shows any interest in the incoming email.

Email service providers, such as Gmail, Outlook, or Yahoo Mail

The number of emails sent to non-existent email addresses is an important parameter for the email service providers on whether senders put enough effort into having good customer relationships: have customers been given the opportunity to subscribe or unsubscribe to a newsletter? And for what duration is a customer considered being engaged with the services of the sender? If this duration exceeds the moment that an email address has become non-existent, and the volume of such email addresses have grown to a sizeable amount, then the sender will be scored with a bad reputation.

The customer’s treatment of the incoming emails is another parameter that the email service providers use for determining the sender’s reputation. Does the customer open the email, moves it to the trash, or marks it as spam? If a customer takes either a negative action or no action for subsequent mailings by the sender, then it’s considered an indicator for the loss of interest in the services of the sender. Persistently sending emails to these customers will also eventually decrease your sender reputation.

Using Email Authentication Systems

The email service providers also make use of systems that determine the authenticity of the sender and the incoming emails. These systems intend to prevent email spoofing; i.e., the creation of email messages with a forged sender address, which is a common tactic among cybercriminals to mislead the recipient about the origin of the email. The most relevant systems are the Sender Policy Framework (SPF), DomainKeys Identified Mail (DKIM) and Domain-based Message Authentication Reporting and Conformance (DMARC).

The Sender Policy Framework (SPF) is one of the most reliable anti-spam techniques, as it aims to prevent spammers and phishers from using your business’ domain name as the “from:” address in their emails. It allows email service providers to check whether the server that sent a particular email was authorized to do so. It does this by verifying the SPF information that is stored in the records of the domain name that is mentioned in the “from:” address of that email.

DomainKeys Identified Mail (DKIM) aims to ensure that an email remains unchanged during the transfer from the sender to the recipient.  It does this by including a cryptographic string to the email. This string consists of elements of the email text that are encrypted using a private key. Email service providers can check the authenticity of an email by requesting the public key which is stored in the records of the sender’s domain name.

Domain-based Message Authentication Reporting and Conformance (DMARC) is an overarching framework in which senders can use both SPF and DKIM techniques. In addition to using the SPF and DKIM authentication systems, DMARC also provides reporting about the actions performed by these systems.

Requirements and Guidelines for Good Practice Email Marketing

Our consultants conceived a list of guidelines for the successful operation of our client’s email marketing campaigns. These guidelines are the result of optimizing the email marketing operations in prior client engagements and are inclusive of the requirements set by the email service providers:

Authenticate your business as a legitimate sender

A set of basic requirements need to be put in place for your email marketing operation to be understood as a legitimate sender by email service providers.

First, emails must be sent using a sender domain name that has a website and one of the prior-mentioned email authentication systems set up: SPF, DKIM, or DMARC.

Furthermore, this domain also needs to be “warmed up” for email marketing by gradually increasing the volume of sent emails each day. Sudden spikes in the number of sent emails could negatively impact your sender reputation.

Use double opt-in

A good email marketing practice starts with giving your customers control over the emails they want to receive. An opt-in strategy to email marketing leads to a lower probability that a customer will mark an incoming email as spam, unsubscribe, or not be opening the email at all.

A double opt-in subscription process means that a customer subscribes to the online store’s newsletter, and confirms this subscription by responding to the welcome email they receive. This process verifies that the subscription to the newsletter is intentional, thus reducing the possibility that incoming emails will be marked as spam.

Optimize the email open rate

Exponea allows you to track whether and when customers open the incoming emails. Real-time analyses of this data reveal the best moments for each of your customers to receive emails. This solution reduces the number of unread emails, therefore also reducing the likelihood of decreasing your sender reputation with each consecutive mailing.

Ensure your mailing list consists of engaged customers

Removing sleeping customers from your mailing list reduces the probability of unread emails. These email addresses also have the risk of becoming non-existent, therefore negatively impacting your sender reputation score.

Customers who are about-to-sleep can best be approached using reactivation emails. These emails should give the customers clear incentives to open the email and visit the online store. Reactivation emails generally re-engage 19% of recipients with your business.

Implementation

Not having any knowledge of these rules and guidelines led to a bad domain reputation for our client among email service providers, and a standstill of their email marketing operation. Our consultants set out to put all these rules and guidelines in place and restart the client’s marketing operation.

Our consultants prepared a re-launch of our client’s email marketing operation using a new domain name. We started warming up this domain using a mailing list that was verified using Mailgun’s email validation service.

New domain names that have a website and an email authentication system in place, start off with a good domain reputation. However, despite that we verified the mailing list for non-existing email addresses, the domain reputation still came down in a short amount of time.

Upon further investigation, our consultants concluded that despite verification, there were still a large number of non-existing email addresses in the mailing list. The leading cause was that the client’s customers had email accounts with one of the local email providers, who were deactivating email accounts after three months of inactivity. Another probable cause could be that the customers ignored and deleted our client’s newsletters because they were no longer engaged.

Our consultants decided to repair our client’s domain reputation by creating several email scenarios in Exponea that takes the degree of a recipient’s engagement with the online store into account. The below table shows the impact of these email scenarios on our client’s domain reputation score.

  1. Instead of using the existing mailing list, we created a new list by displaying a “subscribe to our newsletter” banner on the online store. The visitors who subscribed were then sent a welcome email where they can confirm their subscription.
  2. Once a sufficient number of visitors subscribed to the newsletter, an email scenario was set up in Exponea that measured their engagement with the online store: when a newsletter recipient shows three months of inactivity, the recipient’s email address is removed from the mailing list.
  3. We segmented the mailing list according to how recently the recipient opened the’s recency of opening incoming newsletter. These segments control the email frequency: the more time passes since the last opened newsletter, the fewer newsletters the recipient receives. Further details about these segments are in the below table:

These segments control the email frequency: the more time passes since the last opened newsletter, the fewer newsletters the recipient receives.

Once the domain reputation was restored, our client decided to disable the systems that managed the mailings according to the recency of the recipients. The result was an immediate drop in their reputation score. After two months, the client reached out to our consultants to inquire about this drop. We explained to them that the systems managing that managed the mailings are crucial for attaining a high domain reputation score. Our client’s score increased again after they put these systems back in place.

Aberrations in the spam rate confirm the success of our consultant’s efforts: they indicate that that the attainment of a high domain reputation resulted in the newsletters reaching the recipients’ inboxes instead of their spam boxes. In the case of our client, their spam rate showed a spike of 2.5% of recipients who marked the incoming newsletters as spam as soon as our client received a high domain reputation score. These type of aberrations fall within the margin of error of what email service providers interpret as intentional spam behavior.

Key Learnings

A domain with a bad reputation score can most certainly be repaired. The route towards a good reputation hinges on the email service provider’s perception of your customers’ interest in your newsletters and the degree to which cybercriminals can tamper with your outgoing emails. A bad reputation score is therefore not set in stone but can be turned around by making your email marketing operation compliant with the aforementioned good practice rules and guidelines.

Prevention is, however, the best remedy. It took our client almost three months to recover from a bad reputation score, resulting in a negative impact on their revenue and customer retention.  For that reason, the benefits outweigh the costs involved in authenticating your business as a legitimate sender and ensuring that your email marketing operation reaches the right customer with the right message at the right time.