The following help articles provide some insight into email bounces, but I can't find any detailed info about the questions below and hope someone can answer these.
- Are all the SMTP error codes that start with "4" categorized as a soft bounce?
- Which of the SMTP error codes that start with "5" are categorized as a hard bounce vs. a soft bounce?
- Does the Sales Email Bounced event include both hard and soft bounces?
- Not all hard bounces result in the Email Invalid field being set to "True" - which SMTP error codes cause this to occur?
- Sometimes there is an Email Bounced Soft event (see details below) that occurs in the Activity Log at the same time as the Email Delivered event or several hours later ? Is this because the delivery confirmation SMTP message is sent at a point prior to the point at which the bounce SMTP message is sent and if so, does this mean that the recipient likely did not receive the email? Below are the details for the Bounce events.
- NO MATCH DETECTED
- smtp;400 4.4.7 Message delayed
- smtp; 5.3.0 - Other mail system problem 554-'5.1.0 Sender denied' (delivery attempts: 0)
- 550 [internal] [oob] The response text could not be identified.