Salesforce Bounce Management automatically marks a Lead or Contact's email address as invalid when a permanent delivery failure (bounce) is received from the recipient's mail server (MTA — Message Transfer Agent). This article explains the conditions under which Bounce Management does or does not mark an email address as invalid, and lists the MTA reply strings that trigger a bounce alert.
Once Bounce Management is activated, users can test it by sending an email to a non-existent domain or an invalid recipient at an existing domain.
Important notes:
Salesforce marks an email address as invalid only when the MTA (Message Transfer Agent) that owns the recipient's domain rejects the message with a 5xx permanent error indicating the user is unknown. If the MTA does not return one of the recognized error strings listed below, Salesforce will not mark the email as bounced or invalid.
The following is the list of MTA reply strings that trigger a bounce alert in Salesforce, grouped by category:
Note: For more information on Bounce Management, see Enable Email Bounce Handling.
Enable Email Bounce Handling
Workflow Rule: Email Alert Does Not Utilize Bounce Management Address
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