1. The following error appears when attempting to open Settings > Filter in Roundcube webmail:
Could not connect to Sieve server
var/log/plesk-roundcube/errors log file shows the following:
ERROR: Connection refused (111)
ERROR: Not currently connected (1)
1. Sieve filter is not supported in Plesk 11.5 or older versions. In Plesk 12, Sieve support is provided with Dovecot. A feature request with ID RT #1827961 has been created for the Plesk Service Team and will be considered for inclusion in a future product version.
2. Dovecot's plugin managesieve is not listening to the port.
For Plesk 12:
Switch from Courier IMAP to Dovecot using Plesk autoinstaller: Home > Tools & Settings > Updates & Upgrades > Add\Remove components > Mail > Dovecot .
More about Dovecot is available in developers blog .
More information is available on forums .
Please also see Plesk 12 Release notes .
For Plesk 12.5 and higher:
By default, Dovecot's plugin
managesieve, which is used for managing sieve, is listening to port 4190. Check whether this port is listened:
netstat -tulpn | grep dovecot tcp 0 0 0.0.0.0:993 0.0.0.0:* LISTEN 19933/dovecot tcp 0 0 0.0.0.0:995 0.0.0.0:* LISTEN 19933/dovecot tcp 0 0 0.0.0.0:110 0.0.0.0:* LISTEN 19933/dovecot tcp 0 0 0.0.0.0:143 0.0.0.0:* LISTEN 19933/dovecot tcp6 0 0 :::993 :::* LISTEN 19933/dovecot tcp6 0 0 :::995 :::* LISTEN 19933/dovecot tcp6 0 0 :::110 :::* LISTEN 19933/dovecot tcp6 0 0 :::143 :::* LISTEN 19933/dovecot
/etc/dovecot/conf.d/90-plesk-sieve.conffile. It should contain the following line:
protocols = $protocols sieve
Check that there are no additional
/etc/dovecot/conf.d/*.conffiles with similar lines. If there are, check that they have sieve listed in protocols.