problem kolab login to pop3 and imap

[hansjuergen.riess at t-online.de]

Within kolab I can enter the web interface, create users and so on.
I can login to the users admin interface and change data.
But I cannot login to pop3 or imap :

+OK db.pag.de Cyrus POP3 v2.2.6 server ready
<80454244.1097581923 at db.pag.de>
user riess at sonnenstromag.de
+OK Name is a valid mailbox
pass system
-ERR [AUTH] Invalid login 
user riess
+OK Name is a valid mailbox
pass system
-ERR [AUTH] Invalid login

corresponding saslauthd.log entry :

Oct 12 13:53:00 db <debug> saslauthd[939]: Authentication failed for
riess/sonnenstromag.de: Bind to ldap server failed (invalid
user/password or insufficient access) (-7)
Oct 12 13:53:00 db <info> saslauthd[939]: do_auth         : auth
failure: [user=riess] [service=pop] [realm=sonnenstromag.de]
[mech=ldap] [reason=Unknown]
Oct 12 13:56:08 db <debug> saslauthd[939]: Authentication failed for
riess/sonnenstromag.de: Bind to ldap server failed (invalid
user/password or insufficient access) (-7)
Oct 12 13:56:08 db <info> saslauthd[939]: do_auth         : auth
failure: [user=riess] [service=pop] [realm=sonnenstromag.de]
[mech=ldap] [reason=Unknown]

What is wrong with my machine ???

Thanks in advance

Hansjuergen Riess