Wondering why your emails get bounced?

If you are involved in any kind of email marketing or managing your business or work emails, you must be familar with a term known as "Bounced emails". Bounced emails can quickly pile up if you start ignoring them and can affect the deliverability of your emails. Worst case scenario, they can even cause blacklisting of your entire email list. All the hard work you did to build the email campaign from the ground up to market your brand and business can be wasted if you have been ignoring bounce emails and not doing anything about it.

 

So, before we get into the details, let me know explain - "what is a bounce email?"

When an email message is not delivered to its recipient, it is called a bounce. The bouce is basically a message that is send back by ISPs to your email marketing system when your subscriber cannot receive your email(s). That bounce message is also an explaination (detailed reason) for why the email was not delivered to the recipient / subscriber.

 

Most of the email marketing systems like MailChimp, SendGrid, Exact Target / Salesforce Marketing Cloud or any other mailing service or CRM system puts the bounce messages / reasons in different categories. From my personal experience while working on different CRM platforms like Autotask, ConnectWise, Oracle RightNow & Exact Target / Salesforce Marketing Cloud, these are the most common bounce categories I have seen:

 

1) Hard Bounce

This occurs when an email server is rejecting your email(s) for permanent reasons. Permanent reasons can be: fake email address, temporary disposable email address, email domain does not exists or recipient's email server is not accepting any email messages.

A lot of times, email marketing systems takes care of hard bounce emails automatically by marking them as unsubscribe or excluding them out. But, you should always make sure that you are removing all hard bounce email from your list. In short, hard bounce emails are never going to receive your emails so don't waste your time and money in keeping them in your lists. Keep your email / subscribers list clean from hard bounces. If you can't take them hard bouce emails out, simple make a list of all hard bounce email and create another list that you can use as exclusion while sending your emails.

 

2) Soft Bounce

This occurs when an email server rejects your email(s) for temporary reasons. This is one of the most common bounce types. Temporary reasons can be: recipient's mailbox is full, email file is too large or recipient's email server is down.

There is no need to remove soft bounces right away from your subscribers list. But, if any email address continues to soft bounce in all of your email campaigns then it should be considered as a hard bounce and you should remove it from your list.

 

3) Block Bounce

This occurs when an email server is not trusting your email or rejecting them due to filter issues. Block bounce reasons can be: URL blocks, no proper authentication, complaints issue, blacklisted I.P address or email includes blocked content or URL.

 

FAQ #1: Should I remove all block bounces too from my list (just like hard bounces)?

Answer: You should not suppress or exclude all block bounces in future emails. Instead, you should filter out the block bounce emails and create lists for big domains like AOL etc. These domains always have a threshold limit so for an instance if we have 50,000 block bounce emails, you should separate them in 5 lists of 10k and send email to 1 list at a time (instead of sending email to all 50,000, send one email per day to 10k). This way, big domains like AOL can start accepting our email as long as you stay below the threshold limit. Once, you start seeing less bounce rate, these domains will increase our threshold limit automatically.

 

FAQ #2: How bigger companies and organizations are able to send out mass emails successfully?

Answer: ISPs / email providers usually do not give out a threshold limit number publicly. Each mail server / sender needs to build their own threshold limit with the email providers / ISPs. The bigger companies who are able to send out mass emails successfully to email provides always start with small number of emails and build high threshold limit overtime. 

One of the common errors messages I ahve seen in bounce reports is from AOL, which is “5.3.2 (system not accepting network messages)” which points to 554 RLY:B1 AOL error code: https://postmaster.aol.com/error-codes#554rlyb1

This error states that an email list is breaking AOL’s threshold and block will be removed if the sent email below the threshold.

 

4) Technical Bounce

This occurs when an email server rejects your email(s) due to any kind of technical reasons. Technical reasons can be: email server is busy, there is some kind of network error or issues with the email format.

 

5) Unknown Bounce

This occurs when an email is not delivered and the reason does not fit into any of the over mentioned bounce type categories.

 

According to MailChimp, the average email campaign stats of MailChimp customers by industry is as follows:

 

Updated: December 5, 2016

IndustryOpenClickSoft BounceHard BounceAbuseUnsub
Agriculture and Food Services 24.64% 3.05% 0.59% 0.44% 0.02% 0.29%
Architecture and Construction 24.61% 2.89% 1.50% 1.10% 0.03% 0.36%
Arts and Artists 27.08% 2.86% 0.63% 0.46% 0.02% 0.29%
Beauty and Personal Care 18.41% 1.99% 0.39% 0.40% 0.03% 0.33%
Business and Finance 20.91% 2.74% 0.67% 0.56% 0.02% 0.23%
Computers and Electronics 20.90% 2.21% 1.04% 0.72% 0.02% 0.30%
Construction 22.02% 1.93% 1.58% 1.23% 0.04% 0.43%
Consulting 19.37% 2.25% 0.93% 0.73% 0.02% 0.29%
Creative Services/Agency 22.30% 2.63% 1.10% 0.90% 0.03% 0.37%
Daily Deals/E-Coupons 15.02% 2.29% 0.11% 0.08% 0.01% 0.10%
E-commerce 16.70% 2.36% 0.30% 0.24% 0.02% 0.23%
Education and Training 21.80% 2.64% 0.55% 0.47% 0.02% 0.20%
Entertainment and Events 21.15% 2.34% 0.50% 0.42% 0.02% 0.28%
Gambling 18.37% 3.36% 0.38% 0.48% 0.03% 0.17%
Games 20.79% 3.35% 0.45% 0.52% 0.03% 0.25%
Government 26.14% 3.61% 0.48% 0.39% 0.01% 0.13%
Health and Fitness 21.91% 2.62% 0.48% 0.45% 0.03% 0.38%
Hobbies 28.42% 5.19% 0.32% 0.25% 0.02% 0.23%
Home and Garden 23.75% 3.52% 0.58% 0.41% 0.03% 0.37%
Insurance 21.31% 2.12% 0.78% 0.85% 0.03% 0.26%
Legal 22.46% 3.05% 0.77% 0.67% 0.02% 0.23%
Manufacturing 21.92% 2.37% 1.44% 1.01% 0.03% 0.36%
Marketing and Advertising 17.83% 1.95% 0.77% 0.63% 0.02% 0.28%
Media and Publishing 22.02% 4.68% 0.28% 0.19% 0.01% 0.12%
Medical, Dental, and Healthcare 22.34% 2.44% 0.73% 0.74% 0.03% 0.30%
Mobile 19.39% 2.13% 0.57% 0.62% 0.02% 0.36%
Music and Musicians 22.68% 2.85% 0.58% 0.43% 0.02% 0.29%
Non-Profit 24.87% 2.78% 0.49% 0.41% 0.02% 0.19%
Other 22.99% 2.82% 0.80% 0.62% 0.02% 0.28%
Pharmaceuticals 20.06% 2.54% 0.81% 0.75% 0.02% 0.21%
Photo and Video 25.54% 3.59% 0.73% 0.63% 0.03% 0.41%
Politics 22.10% 2.18% 0.43% 0.40% 0.03% 0.21%
Professional Services 20.61% 2.48% 0.91% 0.73% 0.02% 0.31%
Public Relations 20.00% 1.64% 0.81% 0.61% 0.01% 0.21%
Real Estate 20.83% 1.90% 0.62% 0.52% 0.03% 0.31%
Recruitment and Staffing 20.58% 2.19% 0.53% 0.60% 0.02% 0.31%
Religion 26.35 3.14% 0.19% 0.17% 0.01% 0.12%
Restaurant 21.11% 1.26% 0.24% 0.21% 0.02% 0.25%
Restaurant and Venue 21.57% 1.34% 0.54% 0.47% 0.02% 0.41%
Retail 20.91% 2.53% 0.36% 0.30% 0.02% 0.28%
Social Networks and Online Communities 21.59% 3.37% 0.37% 0.30% 0.02% 0.23%
Software and Web App 20.98% 2.31% 1.07% 0.87% 0.02% 0.39%
Sports 25.36% 3.23% 0.47% 0.42% 0.02% 0.28%
Telecommunications 21.45% 2.45% 1.15% 0.95% 0.02% 0.27%
Travel and Transportation 20.51% 2.19% 0.66% 0.49% 0.02% 0.24%
Vitamin Supplements 17.14% 1.82% 0.29% 0.23% 0.03% 0.26%

 

 

According to MailChimp, the average email campaign stats of MailChimp customers by company size is as follows:

 

Company SizeOpen RateClick RateSoft RateHard RateAbuse RateUnsub Rate
1 to 10 21.44% 2.86% 0.58% 0.45% 0.02% 0.30%
11 to 25 20.57% 2.46% 0.59% 0.47% 0.02% 0.24%
26 to 50 21.35% 2.76% 0.39% 0.30% 0.01% 0.17%
50+ 22.74% 2.77% 0.56% 0.51% 0.02% 0.20%

Hope it helps!

About Author

Written By Lavish Kumar

Based out of New York, USA, Lavish Kumar is a full stack web developer by profession and founder of Striving Programmers, a trusted community for developers that offers a wealth of articles and forums to assist individuals with improving their software development skills.

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