Desktop client issues - certificates

[JB]

Hi all,

I have successfully installed Kolab 3 and have it working with 
Roundcube for sending and receiving email. Unfortunately, using desktop 
clients is being much more difficult. Ironically, Microsoft Outlook is 
being more cooperative than Thunderbird!

I think the issue has to do with the certificate.

Thunderbird simply will not connect, even when I choose Manual 
Configuration, ports 143 & 587 TLS and normal password.

Outlook will configure but delivers the message:

"The server you are connecting to is using a security certificate that 
cannot be verified. The target principal name is incorrect."

When I View Certificate, it shows:

"Issued to: localhost.localdomain" "Issued by: localhost.localdomain"

I have used: /etc/pki/tls/certs/make MyDomain.csr

I then submitted the CSR to GoDaddy and got a zipfile which contained: 
host.mydomain.com.crt and gd_bundle.crt

I uploaded host.mydomain.com.crt and gd_bundle.crt to 
/etc/pki/tls/certs and restarted the server.

I still get the same messages from Outlook, where did I go wrong or 
what step am I missing?

Thanks,

-J