Bounces
If an email was unable to be delivered, an automated response is generated, and the original email is said to have bounced.
Bounces can largely be classed as "Hard" or "Soft"
Hard bounces
This is a permanent delivery error, subsequent attempts to send email to this address are unlikely to succeed. These might occur if a mail server no longer accepts email for a particular recipient, say if their account has been deleted.
Soft bounces
This is a temporary error, subsequent attempts to send email to this address may be successful. This might be because the user's account is full, a system is undergoing maintenance, or a particular message is too large.
Delivery errors
If an error occurs during delivery, Sendamatic will periodically retry the email for up to 36 hours until it either succeeds, or we give up and generate a bounce.
Bounce classifications
Sendamatic classifies bounces for you
| Bounce Type | Description |
|---|---|
| Undetermined | This might be an auto-reply, or a bounce format that the classifier can't understand. |
| Hard bounce | The email server couldn't deliver your email message. If the reputation_score flag is true in the notification message you receive, you should remove this address from your lists. |
| Soft bounce - General | The email server is temporarily unable to deliver your message to the recipient email address. |
| Soft bounce - DNS failure | The email server is temporarily unable to deliver your message to the recipient email address because of a DNS problem. |
| Soft bounce - Mailbox full | The email server is temporarily unable to deliver your message to the recipient email address because the recipient's email box is full. |
| General bounce | The email server couldn't deliver your email message. |
| Mail block - Spam detected | The recipient's email server has rejected the email because the message has content that looks like spam. |
| Mail block - Relay denied | The recipient's email server has rejected the email. |
| Suspension list | The recipient is on Sendamatic's suspension list |
Common general bounce reasons
| Reason | Description |
|---|---|
| Tried all MXs example.com | Sendamatic was unable to make a connection to the example.com mail server |
| Nowhere to deliver mail to for domain: example.com | No mail servers could be found for example.com |
| DNS lookup failure: example.com | The attempt to resolve mail servers for example.com failed |