Hard vs. Soft Bounces


When a recipient server blocks an incoming email, it’s called a bounce. When a bounce happens, the receiving server will usually provide a message stating the reason for that bounce, allowing Privy to categorize them as soft or hard bounces.

In this article, you’ll learn about some specific reasons why bounces can happen, and the effect bounces can have on your contact list.

Hard Bounces

Hard bounces indicate that the email address cannot receive emails permanently. Some of the reasons for a hard bounce might be:

  • The email address is invalid or nonexistent
  • The recipient server is no longer active or has blocked emails permanently
  • The recipient user had a firewall or a strict spam filter

Once an email hard bounces, the recipient address will be automatically and immediately marked as “suppressed: non-mailable”, removing the contact from your mailable contacts list permanently.

Soft Bounces

Soft bounces indicate a temporary issue that is preventing that address from receiving emails at that time. Servers will continue to attempt to deliver the email until a certain amount of time has passed without success before officially sending back a bounce message. Some of the reasons for a soft bounce might be: 

  • Mailbox exceeds storage quota (full inbox).
  • Mailbox configuration is incorrect.
  • Mailbox is inactive.
  • Recipient's email server is offline.
  • Recipient's email server has received excessive emails within a timeframe.
  • Email size exceeds permissible limits.
  • Domain name may be temporarily unavailable.
  • Email content is blocked.
  • Email does not adhere to recipient server policies.
  • Email fails DMARC verification.
  • Email triggers recipient server's anti-spam measures.
  • Email triggers recipient server's anti-virus measures.
  • Email fails sender requirements of recipient server.
  • Email cannot be relayed between servers.
  • Email cannot be relayed due to unknown reasons.
  • Recipient’s email server blocked your message due to sending reputation.

Soft bounces will not cause the email address to be marked as non-mailable but can be persistent depending on the cause.

How to find and analyze your campaign bounce rates and reports

Now that you have an idea of what the difference between hard and soft bounces is, you can better analyze your bounce rates and access the detailed error messages for more information about them.

First, to find your bounce rate on a Newsletter campaign, you’ll just need to click on the desired newsletter, scroll down to the reporting area, and then filter by “Bounced”:

Here you’ll be able to check individual contacts who have returned bounce messages, and by clicking on their email address, you’ll see the separate bounce error messages with more details:

This allows you to correct any possible causes for bounces, as well as get insights on bounce issues that cannot be immediately resolved. 

What is a good bounce rate and how can it be improved?

A good bounce rate will stand at 2% or lower, anything between 2% and 5% is worth investigating and anything over 5% would be considered critical and would require immediate action for improvement.

Major points to take into account when it comes to a high rate of bounces are: 

  • What are the major causes of the bounces? This can be assessed by taking a look at the bounce error messages on your email reports.
  • Are my domain settings within Privy correctly configured? This can be assessed by checking your account’s domain settings page

One other very important thing to note is that since February 2024, Google and Yahoo have set specific requirements for email senders that consist of setting up authentication methods such as DMARC, SPF, and DKIM records to send emails to their users’ inboxes - these requirements can have a great impact on your deliverability and bounce rate, so make sure to keep an eye on that. 

We have an article that goes into more detail about this, but you can also reach out to us for extra help by sending an email to support@privy.com 

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