What is an email bounce?
An email bounce signifies non-delivery of your email message. When this happens, the mailer will receive an automatic notification of the delivery failure. This failure originates from the recipient’s mail server for a number of reasons (explained below).
Soft Bounce vs. Hard Bounce
There are two types of bounces that you can receive – a soft bounce/block or a hard bounce. Think of soft bounces as blocks that are a short-term issue–you don’t need to permanently take these addresses off of your list. However, hard bounces are either invalid or non-existent addresses that should be removed immediately.
A soft bounce means that the email address was valid and the email message reached the recipient’s mail server. However, common reasons it bounced back include:
- The mailbox was full (the user is over their quota)
- The server was down
- The message was too large for the recipient’s inbox
We continue to attempt to send these messages for up to 72 hours until the message is delivered. If a message is continuously deferred for 72 hours, we will stop trying the resend for that particular email, but they will be eligible to receive other sends in the future.
A hard bounce occurs when the message has been permanently rejected either because:
- The email address is invalid
- The email addresses does not exist
We add these hard bounced addresses to a suppression list and they will be excluded from future sends.