|Hard bounce vs soft bounce|
|List of bounce and suppression types|
Sometimes your emails won't get through to your contacts' inboxes. When emails fail in this way, they're known as bounces. When this happens, we'll let you know why something has bounced.
A hard bounce is an invalid email address and will be immediately placed in the suppression list.
A soft bounce is an email address where delivery was unsuccessful (which could be due to a full mailbox, or the recipient's mail server is temporarily unavailable) but it doesn't necessarily mean the email is invalid.
If an email address hard bounces once, or soft bounces too many times, it will be suppressed in your account to prevent you from sending to it. This helps to protect your sending address and server from being blocked for spamming.
You're able to decide how many times a contact can soft bounce before they become suppressed in the Contacts > Suppressed contacts > Bounce settings section of the system.
Setting a lower number helps protect your sending reputation, whilst setting a higher number helps to avoid suppressing contacts who are only bouncing temporarily.
Good to knowSuppressions expire after a year for contacts originally suppressed due to reaching the soft bounce threshold. They won't be automatically added back into your account but they can be uploaded again.
At various points in the system you may see references to bounce types. These are explained below.
- Globally suppressed: Contacts who've either complained directly to us in the past or are known spam traps.
- Hard bouncers: Contacts whose addresses are permanently unreachable, most likely because they, or the server they were hosted on, don't exist.
- Soft bouncers: Contacts whose addresses are temporary unavailable, possibly because their mailboxes are full or their server is having temporary issues accepting mail.
- ISP complainers: Contacts who've submitted spam complaints to us via their internet service provider.
- Mail blockers: Contacts who've received messages that their provider does not want to process, possibly because of attachments.
- Domain suppression: Contacts whose email domain you have previously added to your suppression list.
- Soft bounce: The mail server that handles mail for this email address didn't accept the message when we tried to send it; however, trying again later may succeed.
- Soft bounce - DNS failure: Although we tried several times, we were unable to determine which mail server is configured to accept mail for this email address. This may be due to the correct mail server undergoing maintenance at the times we attempted to send the message.
- Soft bounce - mailbox full: The recipient's mailbox is too full to accept the message you tried to send them.
- Soft bounce - message too large: The recipient's mail server won't accept a message of this size.
- Bounce - no email address: A bounce came back, but the mail server we sent the message to didn't indicate who the bounce was on behalf of. We've identified the intended recipient, based on the content of the message being returned.
- General bounce: The mail server returned the message to us, but didn't indicate a reason why.
- Mail blocked: The mail server indicated that it didn’t want to receive the mail. No reason was given.
- Mail blocked – known spammer: The mail server has decided that your message doesn’t satisfy their filtering criteria, and thinks it may be spam. It has been rejected.
- Mail blocked – relay denied: The mail server says that although the recipient’s domain is pointed at it, it won’t currently accept mail for that domain.