Re: [Dovecot] failing to deliver to one of multiple destinations

No, when delivery fails entirely, the deliver binary should give an
appropriate exit code, indicating that the MTA needs to try again later
or bounce the message. OK, I would have expected that.

What do the Dovecot and MTA logs say?
I will send you that information in private mail.

Furthermore, the output of dovecot -n would help us find and solve the
issue. And finally, your Sieve script may also be relevant. See above.

Thanks for your help.