What is Hard Bounce?
Hard Bounce - a term used in email marketing that refers to an email that is returned to the sender because it was permanently undeliverable. This occurs when the recipient's email address is invalid, closed or no longer exists.
The impact of hard bounces can be damaging to your sender reputation since they indicate to internet service providers (ISPs) and email clients that you are sending emails to non-existent addresses. As a result, ISPs may begin diverting your emails directly into spam folders or blocking them altogether.
To reduce the number of hard bounces, it is recommended that you regularly maintain your email list by removing inactive and invalid contacts.