Kann mich nach Update =?ISO-8859-1?Q? auf 2.3.0.1 nicht me?= hr einloggen

[post at volker-wysk.de]

Hallo!

Ich habe meinen Dovecot-Server von 2.2.22 nach 2.3.0.1 aktualisiert. 
Jetzt kann ich mich nicht mehr einloggen. Mein  Mailprogramm (KMail)
sagt, daß mein Benutzername+Paßwort zurückgewiesen wurde.

Ich bekomme Folgendes in /var/log/auth.log:
Mar  6 19:28:02 desktop auth: PAM audit_log_acct_message() failed:
Operation not permitted

Und in /var/log/dovecot.log:
Mar 06 19:28:02 auth: Debug: Loading modules from directory:
/usr/lib/dovecot/modules/auth
Mar 06 19:28:02 auth: Debug: Module loaded:
/usr/lib/dovecot/modules/auth/lib20_auth_var_expand_crypt.so
Mar 06 19:28:02 auth: Debug: Module loaded:
/usr/lib/dovecot/modules/auth/libdriver_sqlite.so
Mar 06 19:28:02 auth: Debug: Read auth token secret from
/var/run/dovecot/auth-token-secret.dat
Mar 06 19:28:02 auth: Debug: auth client connected (pid=5615)
Mar 06 19:28:02 auth: Debug: client in: AUTH    1       PLAIN  
service=imap    secured session=ggZPmsJmIoh/AAAB        lip=127.0.0.1  
rip=127.0.0.1   lport=993       rport=34850     local_
Mar 06 19:28:02 auth-worker(5617): Debug: Loading modules from
directory: /usr/lib/dovecot/modules/auth
Mar 06 19:28:02 auth-worker(5617): Debug: Module loaded:
/usr/lib/dovecot/modules/auth/lib20_auth_var_expand_crypt.so
Mar 06 19:28:02 auth-worker(5617): Debug: Module loaded:
/usr/lib/dovecot/modules/auth/libdriver_sqlite.so
Mar 06 19:28:02 auth-worker(5617): Debug:
pam(v,127.0.0.1,<ggZPmsJmIoh/AAAB>): lookup service=dovecot
Mar 06 19:28:02 auth-worker(5617): Debug:
pam(v,127.0.0.1,<ggZPmsJmIoh/AAAB>): #1/1 style=1 msg=Password:
Mar 06 19:28:02 auth-worker(5617): Info:
pam(v,127.0.0.1,<ggZPmsJmIoh/AAAB>): pam_authenticate() failed: System
error
Mar 06 19:28:04 auth: Debug: client passdb out: FAIL    1       user=v
Mar 06 19:28:06 imap-login: Info: Aborted login (auth failed, 1 attempts
in 4 secs): user=<v>, method=PLAIN, rip=127.0.0.1, lip=127.0.0.1, TLS,
session=<ggZPmsJmIoh/AAAB>

Und es sieht so aus, als könnte ich auch nicht zurückgehen und wieder
2.2.22 installieren. In https://wiki2.dovecot.org/Upgrading/2.3 steht:
"Downgrading is possible to
v2.2.27 and later. (v2.2.27 accidentally broke dovecot.index* backwards
compatibility a bit.)"

Was soll ich jetzt tun...?

Hier ist mein "dovecot -n":


# 2.3.0.1 (ffd8a29): /etc/dovecot/dovecot.conf
# Pigeonhole version 0.5.0.1 (d33dca2)
# OS: Linux 4.4.0-116-generic x86_64 Ubuntu 16.04.4 LTS
auth_debug = yes
auth_username_format = %n
auth_verbose = yes
auth_verbose_passwords = plain
hostname = volker-wysk.de
log_path = /var/log/dovecot.log
mail_debug = yes
mail_location = mdbox:~/lib/Dovecot-Mail
managesieve_notify_capability = mailto
managesieve_sieve_capability = fileinto reject envelope
encoded-character vacation subaddress comparator-i;ascii-numeric
relational regex imap4flags copy include variables body enotify
environment mailbox date index ihave duplicate mime foreverypart
extracttext imapsieve vnd.dovecot.imapsieve
namespace inbox {
  inbox = yes
  location =
  mailbox Drafts {
    special_use = \Drafts
  }
  mailbox Entwürfe {
    special_use = \Drafts
  }
  mailbox Junk {
    special_use = \Junk
  }
  mailbox Papierkorb {
    special_use = \Trash
  }
  mailbox Sent {
    special_use = \Sent
  }
  mailbox "Sent Messages" {
    special_use = \Sent
  }
  mailbox Trash {
    special_use = \Trash
  }
  mailbox "Versendete Nachrichten" {
    special_use = \Sent
  }
  prefix =
  separator = .
}
passdb {
  driver = pam
}
plugin {
  imapsieve_mailbox1_before =
file:/usr/lib/dovecot/sieve/report-spam.sieve
  imapsieve_mailbox1_causes = COPY
  imapsieve_mailbox1_name = Spam
  imapsieve_mailbox2_before =
file:/usr/lib/dovecot/sieve/report-ham.sieve
  imapsieve_mailbox2_causes = COPY
  imapsieve_mailbox2_from = Spam
  imapsieve_mailbox2_name = *
  sieve = ~/.dovecot.sieve
  sieve_dir = ~/lib/Sieve
  sieve_global_extensions = +vnd.dovecot.pipe +vnd.dovecot.environment
  sieve_pipe_bin_dir = /usr/lib/dovecot/sieve
  sieve_plugins = sieve_imapsieve sieve_extprograms
}
postmaster_address = post at volker-wysk.de
protocols = imap lmtp sieve
ssl = required
ssl_cert = </etc/ssl/certs/dovecot.pem
ssl_dh =  # hidden, use -P to show it
ssl_key =  # hidden, use -P to show it
userdb {
  driver = passwd
}
protocol lmtp {
  mail_plugins = " sieve mail_log notify"
}
protocol lda {
  mail_plugins = " sieve"
}
protocol imap {
  mail_max_userip_connections = 50
  mail_plugins = " imap_sieve"
}


Tschüß
Volker