Horde is configured to use IMAP protocol on my Plesk server. The following error appears when trying to log in to webmail:
Login failed because your username or password was entered incorrectly.
/var/log/psa-horde/psa-horde.log log can contain the following error:
HORDE [error] [imp] FAILED LOGIN
Plain text authentication is, most likely, disabled in the Courier IMAP configuration file.
On the Plesk server, try connecting to localhost via IMAP using telnet:
# telnet localhost 143
Connected to localhost.
Escape character is '^]'.
* OK [CAPABILITY IMAP4rev1 UIDPLUS CHILDREN NAMESPACE THREAD=ORDEREDSUBJECT THREAD=REFERENCES SORT QUOTA IDLE ACL ACL2=UNION STARTTLS] Courier-IMAP ready. Copyright 1998-2004 Double Precision, Inc. See COPYING for distribution information.
01 login email@example.com <password>
01 NO PLAIN text authentication does not support
If the connection is successful, please refer to the following article:
213396949 Horde Webmail login fails: How to troubleshoot
If not, and you see the "
01 NO PLAIN text authentication does not support " message, proceed to the resolution below.
If you are not able to connect through Telnet and seeing message as "Connection refused", then ensure that "courier-imap" service is running. If it is not running, start it with command:
# /etc/init.d/courier-imap start
Enable plain text authentication by editing
Add the AUTH=PLAIN parameter to the values of the IMAP_CAPABILITY variable.
IMAP_CAPABILITY="IMAP4rev1 UIDPLUS CHILDREN NAMESPACE THREAD=ORDEREDSUBJECT AUTH=PLAIN THREAD=REFERENCES SORT QUOTA IDLE"
Do not forget to restart
# /etc/init.d/courier-imap restart