Administer the List - Bounces
Learn to Read Headers and Bounce Messages!
- “Hard” Bounces
- “User Unknown”, “Host Unknown”
- Status Codes begin with “5”
- “Soft” Bounces
- “Connection Timed Out”, “Deferred - Network is Unreachable”
- Status Codes begin with “4”
Unsubscribe Hard Bouncers, or Try to Reach Them or Their Postmaster