When I configure my zimbra email account to ZD, the system always shows the same error that like below:

zclient.IO_ERROR: unable to parse response:
Not Found
The requested URL /service/soap/ was not found on this server.
Apache/2.2.8 (Unix) Server at rueger.com Port 443

I can normally use the email in web site.
How can I fix it? Pls help me!
Thanks a lot!