What are Soft and Hard bounces?

When you excitedly dispatch your latest email marketing campaign, the email server behind each distinct email address found on your mailing list will sternly decide whether your campaign should pass through and reach the intended recipient or whether it should be rejected and bounce back as unwanted.

Bounces indicate that a subscriber's email server has rejected the incoming mail. There are two types of bounces depending on the reason why the campaign was rejected. It is highly recommended to keep an eye on your reports which clearly inform you of the number of bounces of each campaign, so as to take appropriate action and ensure that your campaigns reach nothing but inbox.

A. Soft Bounces

A Soft Bounce indicates that the email address of the campaign's recipient is valid but a temporary delivery issue prevented the campaign from actually being delivered. Moosend will try to resend the email which did not manage to reach the recipient's inbox four more times before it a Hard Bounce occurs. 

The most common reasons why a soft bounce might occur are:

  • the recipient has set an auto-reply mechanics
  • the email you are trying to send is too large
  • the recipient's mailbox is full and cannot receive more email 
  • the recipient's mail server is currently down or offline


B. Hard Bounces

A Hard Bounce indicates a permanent reason why an email cannot be delivered to a specific subscriber's email address. Hard bounced email addresses are automatically removed from your mailing list and transferred to the category tagged as Bounced.

The most common reasons why a hard bounce might occur are:

  • the recipient misspelled their email address while subscribing
  • the recipient has deleted, changed their email address or provided you with a false address
  • the recipient's mail server has blocked your server


To deal with all of the above it is good to get more insight on how Moosend allows you to manage your bounces. Furthermore, it might happen that one of your subscribers accidentally unsubscribes from your list, so being able to quickly add them back in a list or figuring out why specific bounces occurred shows you care about the health of your mailing list and leads to greater results for your campaigns.