We’ve created a system flow that sends e-mails via a ‘queue’ table. We capture the SMTP status code in a process variabele and act according to the response. The SMTP status code will be updated in the queue table.
When testing we try to set-up a recipient with an incorrect e-mail address. The response we expect is status code ‘-4’ (Unsuccessful (one or more addressees could not be reached)) but the result is ‘0’ (Succeeded)
Our task then marks the e-mail as ‘sent’ because SMTP status code 0 is returned. However Outlook itself response with a ‘Delivery has failed’.
Why does the SMTP connector return 0 and not -4?
Best answer by Edo Spijker
Hello,
So I’ve been looking for an answer for your question and this is what I've found out so far.
With smtp you send an email to a smtp server. This server doesn’t have to send it immediately, it could wait until it has more stored mails and send them all in batches for example. From the GUI perspective this is a sort of a fire and forget protocol. This is why you don’t get a exception in this instance, the server accepts that mail and somewhere in the future sends it, only then it gets a rebound mail that states that the recipient is not reachable. The -4 error is only when the server is configured to block outgoing mails to specific mail addresses.
So I’ve been looking for an answer for your question and this is what I've found out so far.
With smtp you send an email to a smtp server. This server doesn’t have to send it immediately, it could wait until it has more stored mails and send them all in batches for example. From the GUI perspective this is a sort of a fire and forget protocol. This is why you don’t get a exception in this instance, the server accepts that mail and somewhere in the future sends it, only then it gets a rebound mail that states that the recipient is not reachable. The -4 error is only when the server is configured to block outgoing mails to specific mail addresses.
