An email bounce occurs when an email cannot be delivered to the recipient’s inbox. There are two types of bounces: hard bounces and soft bounces.
Hard Bounces A hard bounce is a permanent delivery failure. This happens when the email address doesn’t exist, the domain is invalid, or the recipient’s server has permanently blocked delivery. Hard bounces should be immediately removed from your list.
Soft Bounces A soft bounce is a temporary delivery failure. The email address exists, but the message couldn’t be delivered because the mailbox is full, the server is temporarily down, or the message is too large. Soft bounces may resolve themselves, but persistent soft bounces should be investigated.
Impact on Deliverability High bounce rates signal to ISPs that you’re not maintaining a clean list, which can damage your sender reputation and lead to your emails being marked as spam.
How MailClean Helps Our cloud-based verification engine checks every email address before you send, identifying invalid addresses that would cause bounces. With 99% accuracy, you can reduce your bounce rate by up to 98%.