Message.bounced_detected not detecting certain types of bounce messages

Hi there,

It seems Nylas can’t detect certain types of bounces, or its bounce detection is unreliable. For example:

  • When the server returns a deliery incomplete, will try later, and then finally returns “message not delivered” (The recipient server did not accept our requests to connect. For more information, go to FAILED_PRECONDITION: connect error (111): Connection refused]

  • When the server returns a bounce from another domain:
    " This is a delivery failure notification message indicating that
    an email you addressed to email address :

could not be delivered. The problem appears to be :
– Recipient email address is possibly incorrect

Additional information follows :
– 5.4.1 Recipient address rejected: Access denied.
"

  • When the server returned a bounce notification in other language: "Échec de la remise pour ces destinataires ou groupes :

Nous n’avons pas trouvé l’adresse de courrier que vous avez entrée. Vérifiez l’adresse de courrier du destinataire et essayez de renvoyer le message. Si le problème persiste, contactez l’administrateur de votre courrier."

The first case was not detected by any webhook (i have configured thread.replied, message.bounce_detected and message.created) and the second and third case are detected by thread.replied.

Is this expecting behaviour? Just asking because then I’m considering just to inspect all messages received by a custom solution instead of relying in the webhook.

@kikiriki thanks for sharing, let me take a look and circle back soon!

@kikiriki just connecting with the Eng team, are you able to provide the reproduction steps for each scenarios to pass along?

Also, just to confirm - have you taken a look at the Send Dashboard that shows bounced messages?