LinuxQuestions.org - [SOLVED] Webmail interface could not log on to timsieved

I ported a mail server from RHEL4 to RHEL6 (Red Hat Enterprise Linux Server release 6.3). It has a cyrusd running and email via IMAP works in principle fine.
My problem is with a Squirrelmail webmail interface on another RHEL6 server. It connects fine to the mailserver and can send and receive emails. The problem is with the avelsieve plugin. As soon as I enable it the interface reports to any logged in user:

"Could not log on to timsieved daemon on your IMAP server imap.my.domain.top:2000.
Please contact your administrator."

The plugin worked with the old server and the new one has - to the best of my knowledge - the same IP, hostname and firewall settings (port 2000/tcp is open).
Currently I am trying to get version 1.9.9 (alpha) running where as far as I remember 1.9.8 (alpha) was the version that worked before on the old server (but not on the new one either).

I can ping the server and the telnet connection looks fine:

Code:

 # telnet imap.my.domain.top 2000

 Trying 192.164.0.1...

 Connected to imap.my.domain.top.

 Escape character is '^]'.

 "IMPLEMENTATION" "Cyrus timsieved v2.3.16-Fedora-RPM-2.3.16-6.el6_2.5"

 "SASL" "DIGEST-MD5 CRAM-MD5 GSSAPI"

 "SIEVE" "comparator-i;ascii-numeric fileinto reject vacation imapflags notify envelope relational regex subaddress copy"

 "STARTTLS"

 OK

The settings in /etc/imapd.conf are:

Code:

...

sievedir: /var/lib/imap/sieve

...

sieve_maxscriptsize: 512

...

Where these are the permissions for the sieve directory:

Code:

# getfacl /var/lib/imap/sieve

getfacl: Removing leading '/' from absolute path names

# file: var/lib/imap/sieve

# owner: cyrus

# group: mail

user::rwx

group::---

other::---

The user running the imap daemon is indeed cyrus:

Code:

# ps aux | grep imap

cyrus      461  0.0  0.1 119000  3460 ?        S    Jan07   0:10 imapd -s

...

My settings in /etc/cyrus.conf are:

Code:

...

SERVICES {

  # add or remove based on preferences

...

  sieve         cmd="timsieved" listen="sieve-filter" prefork=0

...

}

...

I tried also "sieve" and "192.164.0.1:sieve" instead of "sieve-filter".

I disabled TLS in my /usr/share/squirrelmail/plugins/avelsieve/config/config.php

Code:

...

$sieveport = 2000;

...

$avelsieve_disabletls = true;

...

I even disabled the firewall completely but this did not help. Do you have any ideas which settings I could try or how to debug the problem? It is urging me quite a lot (although you need not to be urged of course) because lots of users need to disable their vacation responders after the holidays.