[Dovecot] dovecot deliver mail bounce problem

[Dhaval Thakar]

Hi list,

I am using dovecot deliver for the local mail delivery with qmail.
this is working fine.

but when mail is sent to invalid user, it gets bounced back with error 
"I'm not going to try again; this message has been in the queue too 
long." rather "no mailbox here by that name"

I could find proper solution,
kindly guide to resolve it.

/var/log/maillog
Oct 24 23:03:27 backup dovecot: auth(default): master in: USER  1       
d at arch.xyz.com       service=deliver
Oct 24 23:03:27 backup dovecot: auth(default): vpopmail(d at arch.xyz.com): 
lookup user=d domain=arch.xyz.com
Oct 24 23:03:27 backup dovecot: auth(default): vpopmail(d at arch.xyz.com): 
unknown user
Oct 24 23:03:27 backup dovecot: auth(default): prefetch(d at arch.xyz.com): 
passdb didn't return userdb entries, trying the next userdb
Oct 24 23:03:27 backup dovecot: auth(default): master out: NOTFOUND     1

no logs in /var/log/dovecot-deliver.log

following is the configuration
.qmail-default
|/var/qmail/bin/preline -f /usr/local/libexec/dovecot/deliver -n -e -d 
$EXT@$USER



dovecot -n
# 1.1.5: /etc/dovecot/dovecot.conf
protocols: imap
ssl_disable: yes
disable_plaintext_auth: no
login_dir: /usr/local/var/run/dovecot/login
login_executable: /usr/local/libexec/dovecot/imap-login
login_greeting: mail ready.
mail_plugins: quota imap_quota trash
imap_client_workarounds: delay-newmail outlook-idle
namespace:
  type: private
  prefix: INBOX.
  inbox: yes
  list: yes
  subscriptions: yes
auth default:
  mechanisms: plain login
  verbose: yes
  debug: yes
  debug_passwords: yes
  passdb:
    driver: checkpassword
    args: /home/vpopmail/bin/vchkpw
  userdb:
    driver: vpopmail
  userdb:
    driver: prefetch
  socket:
    type: listen
    master:
      path: /var/run/dovecot/auth-master
      mode: 384
      user: vpopmail
      group: vchkpw
plugin:
  quota: maildir
  quota_rule: Trash:ignore