At Do we still want to reject CC or Bcc emails in?, it says:
When I send an email To someone (unrelated to my Discourse instance) and BCC a category incoming email address on my instance, I see the following error:
Incoming Email Details
Happens when none of the email addresses in To/Cc/Bcc fields matched a configured incoming email address.
The rejection email that is sent only includes the address used in the To field:
We’re sorry, but your email message to [“email@example.com”] (titled Test event email) didn’t work.
None of the destination email addresses are recognized, or the Message-ID header in the email has been modified. Please make sure that you are sending to the correct email address provided by staff.
Is this expected behavior? If so, how do I use an incoming email address for a use case where I am sending an email to someone or some list and also want to create a topic in a category on my Discourse instance?
PS: I tested with Cc field and that works. So perhaps, the logic to process emails is only looking at message headers that do not include the Bcc field (for obvious reasons). It will be great if we could use Bcc, however, to prevent people from replying all to Discourse instance (if we do not want them to by bcc’ing).