Reasons why emails bounce
It's important to differentiate between hard bounces and soft bounces. Soft bounces occur because of reasons temporary in nature. The most common reasons are as follows:
- the recipients mailbox is full
- the email server is temporarily offline
- your email is too large
In the event of a soft bounce, more delivery attempts will follow. Typically this will take no more than 72 hours. If the email hasn't been delivered by then, it will 'hard bounce'.
Hard bounces are permanent in nature. No second delivery attempts will be made. Typical reasons for this are:
- the email address does not exist
- the email address is invalid
- the mailbox has been disabled
- the domain name does not exist, has been quarantined or has been suspended by the registry
- the recipient server has been instructed to reject your email
- the recipient server refuses to accept your email because of an incorrect configuration on the sending side
To maintain good list hygiene, it's important to remove email addresses that have recorded a valid hard bounce from your email lists. However, if you think mails to a certain email address should not have hard bounced, contact Support to look into the error messages together to resolve the issue.
Always include an unsubscribe link in every email sent. This is required by law in many jurisdictions. Unsubscribes are handled by our email service provider.