What is a Soft Bounce the result of?

A soft bounce refers to a temporary delivery failure that occurs when an email cannot be delivered to the recipient's inbox but is not due to a permanent issue. This can happen for several reasons, such as the recipient's mailbox being full, the server being temporarily unavailable, or the recipient's email client rejecting the email size or other parameters. Soft bounces indicate that the issue may resolve itself, allowing future attempts to deliver the email to potentially succeed.

In contrast, situations such as a permanent delivery failure would indicate a hard bounce, where the email address is invalid or no longer in use. Similarly, issues like a bad attachment or an unauthorized IP address do not represent the temporary nature of a soft bounce, making the classification of soft bounces specifically tied to temporary issues in email delivery mechanisms.