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Top Reasons For Email Bounces With Solutions

Reasons for email bounces with solutions

In nearly half of the U.S., B2B marketers rely on email marketing channel to reach their potential customers. Unfortunately, this marketing channel has few technical drawbacks like email bounces, low click rates, and spammers. Among these email bounce is one of the most annoying obstacles faced by B2B marketers while executing email marketing campaigns. An email bounce is nothing but the sender fails to deliver emails to the potential customers due to various reasons which are hard to identify.


Probably the sent email is not accepted by the business or ISP’s mail server for certain email address and the sent email returns with a code. Where the code states the reason for the rejection of an email sent by the marketer. Based on these reasons email marketing industries have widely categorized email bounce into hard and soft bounce. According to a few email bounce management tool reports, emails usually bounce back to your inbox due to various reasons like:

Invalid email list

The main cause for an invalid email address is poor source of data, manual data entry, and multiple users updating the email database. Today most of the B2B marketers rely on third party data vendors to get accurate email lists of their prospects. These data providers may fail to collect information from the reliable source or may fail to understand the metrics to incorporate while creating the desired email list of the prospects. Manual data entry usually causes typos while collating the customer’s email address.


Ultimately, an email list with inaccurate email addresses is left for the B2B marketer to launch an email marketing campaign. Let’s understand how this invalid email list results in email bounce with the help of an example: Consider a B2B marketer who owns an invalid email list of the prospects and invests for an email marketing campaign. Here the email marketing campaign results in lower ROI, as most of the emails bounce back to the sender’s inbox. A detailed inspection revealed that sent emails were either blocked by ISP servers or dropped into spam list at the customer’s inbox.


ISP server is a part of email architecture that directs all emails with an invalid email address of the recipients towards sender’s inbox. The email address of these emails may have typos due to manual data entry or the email address may not exist. And in other cases, the accumulation of emails at receiver’s spam list is mainly due to collection of invalid customer’s email address. This might also be because the receiver is no longer interested to receive the updates on the company’s products and services. Thus, receiver directs the irrelevant emails into spam list.


To avoid these issues, B2B marketers should focus on building an accurate email list with a valid email address of the recipient that is free from typos. Else the B2B marketer should purchase an email lists from reliable data provider who can understand their needs and build an effective B2B contacts email list.

Insignificant email sender reputation:

Whenever an organization sends an email to its prospects, it passes through several servers like ISP, SMTP, POP3 server and so on depending on the E-mail architecture. The ISP server assigns a score called email sender reputation that measures the deliverability rate of an email. An email with higher email sender reputation score is more likely to reach recipient’s inbox. Moreover, emails with lower score fall in to the spam folder or get rejected. Various factors like number of recipients and spam complaints will influence the email sender reputation score. Unfortunately, ISP server flags the sent emails if it crosses the limits. For example: As of August 2018, an organization can use Gmail suite to send around 3000 emails per day for external recipients with unique email address. If an organization exceeds the limit then ISP server flags the sent emails and thus lowers the email sender reputation score. According to resources even the accumulation of emails in spam folder also reduces the sender reputation score.


Keep track of the number of recipients while sending emails to maintain the email sender reputation score above the threshold value so that your organization can reduce the email bounce rate.

Sender fails to provide identity at recipient’s ISP:

In recent years, many companies and email recipients were prone to internet phishing and spam emails. To avoid such scenarios few protocols are deployed at receiver’s servers to identify and block such emails. Usually at the receiver end the servers look for SPF (Sender Policy Frame Work), DKIM (Domain Keys Identified Mail) and DMARC (Domain-based Message Authentication, Reporting & Conformance) validation process that checks the sender’s identity. If the organization fails to provide its identity at any of these validation processes then its email bounces back with relevant error messages.


Organizations that focus on email marketing should own a SPF protected domain, each email messages should include DKIM. In addition to this, companies have to apply DMARC policies to prove its identity at recipients end.

Email list decay:

In this scenario, company fails to update its B2B contact email list on a regular basis and the customer details change very often due to various reasons like change of job, place, family name and so on. In fact, Marketing Sherpa revealed that the rate of B2B email list data decay is around 2.1% per month. Moreover, the email lists end up with inactive customers who are no more interested in the company’s products or services. In such scenarios, if the B2B marketer uses these email lists to launch an email marketing campaign, then most of the emails bounce back, as most of the recipients may not exist. Alternatively, the recipient may divert the emails into spam folder, as they are not interested in the company’s products or services.


B2B marketers need to update email list data on a regular basis to avoid email list decay and retain only accurate information about customers. Eventually, these key reasons for the occurrence of email bounce and the solutions will guide all B2B marketers to execute a successful email marketing campaign. This in-turn enhances ROI with better marketing revenue. However, any marketer looking for accurate B2B contact email lists can reach us at

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