Delivery of mail to multiple "to" addresses when one address is invalid about msmtp HOT 3 CLOSED

There is no builtin option to "split" a mail and send for each recipient individually.
But you could implement this with a script that handles the mail before msmtp does: read the mail, extract all recipients, call msmtp for each recipient individually, passing the recipient on the command line and avoiding -t/--read-recipients.

from msmtp.

Thanks for a quick reply, Martin! Is it possible to receive feedback from msmtp about which email addresses where rejected or which were valid if we send to multiple addresses at once?

from msmtp.

Msmtp prints information about where in the SMTP session an error occurred, and what the error message given by the SMTP server was.

So I would expect a message like recipient address %s not accepted by server: <MESSAGE-FROM-SERVER>.

However, what you get depends on the SMTP server. It may chose to reject the mail only after all RCPT TO commands have been accepted, and then just give a generic error code and no detailed message.

Postfix typically gives you detailed information.

from msmtp.