"Cannot connect to "imap.gmail.com:993". Please check host/port and network connectivity."

I have an email address at my domain, hosted at gmail apps.

I get the above error message every time I try to add new account (startup screen for Zimbra)

my settings:

imap.gmail.com port 993
smtp.gmail.com port 587

I am using Zimbra Desktop 1.0.4 (build 1833) on Windows 7 Professional operating system.

When I type telnet imap.gmail.com 993 on my command prompt .it gives me error "'telnet' is not recognized as an internal or external command,
operable program or batch file.".