Re: LMTP: Undelivered Mail Returned to Sender: User doesn't exist! :-(

:-)

...

I think that id dovecot handles mailboxes correctly over imap/pop it can easily find the users and their mailboxes so it doesn't need any additional configuration for LDAP. Unfortunately it doesn't work and results in:

Undelivered Mail Returned to Sender: User doesn't exist! :-(

What's the thing I've missed?

If your usernames do not have a domain, you need to configure auth to lookup users by local part only.

Depending a bit on situation, sometimes it's better to do

auth_username_format = %Ln

Exactly, that's the thing I missed (removing a domain suffix). Now it works fine, thank you.

Best regards, Marek