Roundcube send error

I am trying to use roundcube for mail, and I get the following error when I try to send mail: "failed to send message"

The roundcube error log shows:
[06-Jan-2009 16:00:28 -0500] SMTP Error: SMTP error: Authentication failure: Invalid response code received from server (Code: 454) in /var/www/html/roundcubemail-0.2/program/steps/mail/func.inc on line 1248 (POST /roundcube/?_task=mail&_action=send)

and the exim log shows:
2009-01-06 16:00:28 TLS error on connection from (www.odmtech.com) [127.0.0.1] (SSL_CTX_use_PrivateKey_file file=/etc/exim.key): error:0B080074:x509 certificate routines:X509_check_private_key:key values mismatch

To me that looks like roundcube is trying to make an SSL connection, but the rc config file has:
// use this host for sending mails.
// to use SSL connection, set ssl://smtp.host.com
// if left blank, the PHP mail() function is used
$rcmail_config['smtp_server'] = 'localhost';

// SMTP port (default is 25; 465 for SSL)
$rcmail_config['smtp_port'] = 587;

which to me looks like it shouldn't be using tls.

Can anyone suggest what to look at next?

Thanks,
Ord

Update:

worked around that problem by creating a new self signed key/certificate pair for exim.

I'm still not sure why it was needed, but a least it's working now.

I'm in the same situation, but I solved it by change the exim.key & exim.cert permission to 444, the original permission is 440.
There's another solution is modify the $rcmail_config['smtp_server'] = 'localhost'; to $rcmail_config['smtp_server'] = '';in the roundcube/config/main.inc.php, in order to use the php mail() function, skip the IMAP protocol, but it's not recommend.

If you've made your exim.key 444, then anyone can read it (steal it) and along with the exim cert, pretend to be you for the purposes of stealing email. How about 400 for the key and 444 for the cert? That's a lot more secure.

Jeff

Thanks Jeff, but I do try to set exim.key to 400, and the roundcube shows the authtication failed message again, and I tried to chown and chgrp to webapps but didn't work out.

Do you know what is the best solution to this question ? There is nothing I can do in such situation ...

[04-Nov-2009 17:43:09 +0800]: SMTP Error: SMTP error: Authentication failure: Invalid response code received from server (Code: 454) in /var/www/html/roundcubemail-0.3.1/program/steps/mail/func.inc on line 1365 (POST /?_task=mail&_action=send)

I can't figure it out without logging into your server, and as you know if you've read a lot of my posts, I only offer that as a commercial service. Hopefully someone else will have a better idea, or you'll be lucky and no one will steal your key.

However you are giving your clients a false sense of security; they're presuming your key is secure.

Jeff