Compliance, abuse & spam Issue
What are Out of Band Bounces (OBB)?
Understanding OBB (also known as Asynchronous Bounces):
Definition:
Emails initially accepted by recipient server
Later rejected for various reasons
Bounce notification sent after initial acceptance
Common Causes:
Invalid email address verification
Full mailbox detection
Delayed spam filter triggers
Server policy changes
Best Practices:
Monitor OBB patterns
Process bounces promptly
Update suppression lists
Review sending practices