- Plesk Onyx for Linux
When going to Roundcube > Settings > Filters, the following error is shown
CONFIG_TEXT: Unable to connect to Sieve server
The errors below can be found in the
CONFIG_TEXT: ERROR: Connection refused (111)
CONFIG_TEXT: ERROR: Not currently connected (1)
CONFIG_TEXT: PHP Error: Unable to connect to managesieve on localhost:4190
Courier-IMAP shown as installed as the IMAP/POP3 server in Plesk > Tools & Settings > Mail Server Settings.
Courier-IMAP doesn't support Sieve.
Install Dovecot as IMAP/POP3 server:
Go Tools & Settings > Updates and Upgrades > Add and Remove Product Components > Mail Hosting and install Dovecot:
Note: Dovecot configuration used by Plesk is compatible with Courier and acts as a drop-in replacement.