No more bouncing emails! How to make sure your emails arrive correctly.

02.12.2020 1,186 0

You might not know what bouncing emails are, but let me tell you a short story:

Once a close friend started a business. He invested a lot of time and money to get everything ready. He carefully analyzed the market to define potential clients. This guy personally sent several strategically targeted cold emails to these clients. 

Weeks passed, but nobody answered. My friend had never expected such a massive failure. Having checked the great proposals, the writing style, etc., multiple times, he totally panicked when nobody responded! One day, he talked with one network administrator, and the painful truth was revealed – the e-mails never reached the potential clients. There was a bouncing email problem! 

What is a bouncing email? A fatal wound for your business.

There are a few elements of sending and receiving emails: 

Sender – an account that sends emails. He or she uses software, needs a domain and a mail server to send emails. 

Channel – the message will travel through the internet, hopping from server to server and passing through firewalls and filters. 

Recipient – an account that receives emails. He or she uses software, needs a domain and an incoming mail server to receive emails. 

If the transfer process of the message fails, you will be informed about the delivery failure. 

*Feedback – the answer or the messages and codes that will help you understand what happened to the sent email. You might never receive any feedback. It depends on the bouncing type.

To put it plainly, bouncing emails are emails that don’t reach the recipient inbox. A negative impact on your business is a real possibility: 

  • Your business’ reliability could be affected.
  • It can seriously damage marketing strategies and results.
  • It’s a severe obstacle to reach your target.
  • Your messages are at risk to be considered spam by filters.
  • A high bouncing rate can have a sender’s IP address thrown in a blacklist.
  • Waste of time.

Email bouncing types

It’s better to get involved in the topic, know the causes, and how to prevent bouncing when it comes to your business.

General bouncing

This is a common and not so harmful bouncing email. Normally, it is related to the technical server’s limitations. For instance, the firewall settings of the recipient can be restricting your emails.

Soft bouncing

You experience soft bouncing when it is a temporary condition. The recipient’s mailbox can be just cluttered or your email could be exceeding the mailbox limit. Or maybe, the recipient can’t receive emails because their server is down, facing technical issues or delivering/receiving a big load of emails simultaneously.

Hard bouncing

Hard bouncing is the permanent condition of delivery failure. The email address of the recipient is invalid, inactive, non-existent, or maybe, the domain has expired. It can happen due to errors while typing email addresses too. If you type in a single letter or dot incorrectly, the email address recipient won’t be found by the server.

Auto replies

This is one of the most common bouncing types. Maybe everybody has experienced it at least once. You urgently need some info, so you send a message and what you get is an immediate, automated reply and not what you expected.

Transient bouncing

This email bouncing happens when the emails’ delivery takes longer than expected. Normally, it’s just a delay and the delivery should be executed by the server, without a specific sender action. It can happen from time to time, but if it’s frequent, it becomes hard bouncing.

Bouncing by blocking

Security is an important main concern for users, so servers are constantly improving their filters. An email can be blocked by a server if it’s considered spam, if it includes suspicious links or if the sender IP address is detected as blacklisted.

How to prevent bouncing? 

Bouncing can be annoying but the good news is you can make sure your emails arrive correctly!

Validate emails

You can verify your emails with the Sender Policy Framework (SPF). The receivers’ mail server can use it to check the SPF record for the domain of the sender and verify it. 

In the SPF DNS record, there could be extra information like IP addresses that are allowed for the domain. 

Some DNS knowledge could be needed, but you can benefit greatly from it. 

The SPF works best in a combination with DMARC.

Authenticate emails

Use DMARC for authentication. It “fixes” the SPF method and its problem of checking only the return path of the domains instead of the “From” domain that shows in the emails as well. 

It matches the “From” domain and the one that we can see with the SPF. 

DMARC also needs to be set up on the DNS level. If you start using it, you will get far fewer bouncing mails, statistics for sent emails and you can set policies for failed emails. 

Furthermore, you can use DKIM (domain keys identified mail) to sign the emails when sending. 

Frequently update your email list

People can abandon or purposely change email addresses. Domain names can expire. Contacts can move to other companies, get promotions, or get fired. There are many reasons to abandon an account but the result for you (as a sender) will always be negative, bouncing. 

Update the email list of recipients for your campaigns to successfully reach their destination. Remove all inactive email addresses and check for possible typos. There are verification tools that can give you a hand with this task. 

Try double opt-in

You can really get a reliable email list. After clients or users register their accounts in your mailing list, you can add an extra step for them to verify the emails. This process will reduce fake email addresses from your mail list, leaving just authentic accounts. 

Avoid typographical errors

This is a very common but unacceptable mistake, especially when business profit is involved. Currently, people use tools to schedule and send critical business info, or a campaign to multiple recipients. Yet, many companies do this manually. So write email addresses properly and double-check them before sending the message.

Evade common spam signals in the emails’ content

The way we write the messages can look suspicious for spam filters, so be careful. 

Some words are already blacklisted by several email providers because they are frequently included in promotional content: “off”, “60%”, “for free”, etc. Don’t use them.

Use exclamation marks, capital letters, and bold effects without abusing them. They are common resources from promotional materials, so they can trigger spam filters.

Another hint is not to include too many links in the message. This content can be considered a phishing attempt. So your message won’t reach the recipient. 

Of course, it is important to make your message attractive. Just don’t go overboard with code. Users like to view rich content but too much coding (HTML or another) can directly classify your email as promotional material and be sent to the spam folder or another wrong folder.

Don’t harass recipients with emails

Usually, behind the delivery of emails, there’s a strategy with a set contact frequency. Sending multiple, consecutive messages could affect your image but can also be taken as non-human, but rather robotic activity. So your emails could be blocked by the server or even by your own recipient.


Bouncing emails can really affect your business reliability and income. It could happen to anyone but there are ways to fix and prevent it. Just take action! Don’t leave your success to chance. Make sure emails and marketing campaigns arrive correctly to your recipients. Good luck!

You may also be interested in the following articles:

Is having your own mail server a good idea?

How to setup a free mail server on Windows Server – hMailServer, MailEnable and Apache James

Check them out.

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