[imp] "No supported IMAP authentication method could be found" when trying to login

[Ramon Darrow]

I'm trying to setup a fresh install of IMP 4.1 to talk to an Exchange
IMAP server.  However, whenever I attempt to login with a valid
user/password combo I get the following error:

Apr 13 07:40:52 HORDE [notice] [imp] 192.168.2.1 No supported IMAP
authentication method could be found. [on line 42 of
"/var/www/localhost/htdocs/horde/imp/login.php"]

Funny thing is if I attempt to login with an invalid user/password combo
i get the "Login failed" error you would expect if IMAP authentication
is working (which means it is talking to the IMAP server at least):

Apr 13 07:58:18 HORDE [error] [imp] FAILED LOGIN 192.168.2.1 (forwarded
for [unknown]) to mail.worrad.com:993[imap/ssl] as rdarrow [on line 262
of "/var/www/localhost/htdocs/horde/imp/lib/Auth/imp.php"]

The test.php page successfully connected to the remote IMAP server and I
am using the configuration it suggested after testing the connection to
the IMAP server.

One thing I do notice about the logs is that the IP address in the logs
for communications with the IMAP server is actually the IP address of
the DMZ interface on the firewall (the IMAP server is in the LAN).  The
DNS name mail.worrad.com resolves correctly to the IMAP server, so I'm
not sure why the address in the logs is for the firewall instead of the
IMAP server.  That may not matter at all because IMP is talking to the
IMAP server at least enough to deny authentication for wrong
user/password combos.

I appreciate any help anyone can give me.  Thanks.

Ray