I am new to Zimbra, and I must say I LOVE this product. Great job!! I do have one issue...We installed Zimbra without the HTTPS option and that we can send email with authentication enabled (on the client side), but if we enable TLS on the server and the client (Outlook or Thunderbird) is configured accordingly to server parameters, we get a no respond from the server. When TLS is enabled however, we can send/receive everything perfectly from webmail. Any assistance would be MOST appreciated. Thanks in advance!