telnet <my.server.here> 143

<my_name>@<my_host>:~$ telnet <ip> 143
Trying <ip>...
Connected to <ip>.
Escape character is '^]'.
* OK [CAPABILITY IMAP4rev1 UIDPLUS CHILDREN NAMESPACE THREAD=ORDEREDSUBJECT THREAD=REFERENCES SORT QUOTA IDLE ACL ACL2=UNION] Courier-IMAP ready. Copyright 1998-2011 Double Precision, Inc.  See COPYING for distribution information.
a login incoming <my_cool_pwd>
* BYE Temporary problem, please try again later
Connection closed by foreign host.

Oct 18 17:37:23 <my_host> imapd: authdaemon: s_connect() failed: No such file or directory
Oct 18 17:37:23 <my_host> imapd: authentication error: No such file or directory

Oct 18 17:37:10 <my_host> imapd: Connection, ip=[::ffff:xxx.xxx.xxx.xxx]
Oct 18 17:37:23 <my_host> imapd: authdaemon: s_connect() failed: No such file or directory
Oct 18 17:37:23 <my_host> imapd: LOGIN FAILED, user=incoming, ip=[::ffff:xxx.xxx.xxx.xxx]
Oct 18 17:37:23 <my_host> imapd: authentication error: No such file or directory

sudo authtest incoming <my_cool_pwd>

ERR: authdaemon: s_connect() failed: No such file or directory
Authentication FAILED: No such file or directory

Authentication succeeded.

     Authenticated: <login>  (system username: <login>)
    Home Directory: /home/<login>
           Maildir: (none)
             Quota: (none)
Encrypted Password: <hidden>
Cleartext Password: <hidden>
           Options: (none)