How can I check that POP3/IMAP Plesk services are running OK on the server ?

Login to the Plesk server in command prompt and try "telnet localhost 110" (143), if Plesk POP3/IMAP services work an output for login session should be:

# telnet localhost 110
Trying 127.0.0.1...
Connected to localhost.localdomain (127.0.0.1).
Escape character is '^]'.
+OK Hello there.
user USER@DOMAIN.TLD
+OK Password required.
pass PASSWORD
+OK logged in.
list
+OK POP3 clients that break here, they violate STD53.


# telnet localhost 143
Trying 127.0.0.1...
Connected to localhost.localdomain (127.0.0.1).
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.
a001 login USER@DOMAIN.TLD PASSWORD
a001 OK LOGIN Ok.


where USER@DOMAIN.TLD and PASSWORD are mail user name and the password accordingly.


If you run "telnet localhost 110" (143) on the Plesk server and see something like:

telnet localhost 110
Trying 127.0.0.1...
telnet: connect to address 127.0.0.1: Connection refused
telnet: Unable to connect to remote host: Connection refused


Check if courier-imap is running:

ps ax | grep courier


If you see no output, try to start Courier-imap through Plesk CP or from the command line: "$PRODUCT_RC_D/courier-imap start".
Check /var/log/message and $PRODUCT_ROOT_D/var/log/maillog for possible start up errors.

If you see the password error during POP3/IMAP login, check that you use the right mail user name and the password, you may change them through Plesk CP to be sure. Also try to run courier-imap with the default configuration. To do it, backup original /etc/courier-imap/imapd (/etc/courier-imap/pop3d for POP3) and replace it with /etc/courier-imap/imapd.dist (/etc/courier-imap/pop3d.dist). Then restart courier-imap and try to login again. In case of success compare the original and *.dist files in order to find the option that cause the problem.