Glossary Term
Hard Bounce
A permanent email delivery failure, typically because the email address or domain doesn't exist.
What is Hard Bounce?
A hard bounce is a permanent delivery failure where the email cannot be delivered and will never be deliverable to that address. Common causes include:
- Invalid email address: The address doesn't exist (typo, made-up)
- Domain doesn't exist: The domain has expired or never existed
- Permanent block: The recipient's server permanently blocks your sender
- Mailbox deleted: The recipient's account no longer exists
Hard bounces are serious because: 1. They prove you're sending to bad data 2. Email providers track your hard bounce rate 3. Continued hard bounces damage reputation quickly
Best practice: Remove hard bounced addresses immediately and never send to them again. Use email verification before sending to prevent hard bounces.
Why It Matters
- 1Permanent failures that damage sender reputation
- 2Indicates poor list quality or outdated data
- 3Should be removed from your list immediately
- 4High hard bounce rates can lead to blacklisting
Related Tools
Related Guides
Related Terms
Bounce Rate
The percentage of sent emails that fail to deliver and are returned by the receiving server.
Soft Bounce
A temporary email delivery failure that may resolve itself, such as a full mailbox or server issue.
Email Verification
The process of confirming that an email address is valid, deliverable, and belongs to a real person.
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