Unable to setup sync with Android

Unable to setup sync with Android

I followed the instructions from http://zsync.zohosites.com/Android.html to sync my zoho calendar with my Android phone, but I keep getting the error message "Unable to connect to server" when I click Next after filling out the Domain/Password/Exchange server fields. My internet connection is working well. Phone is Galaxy S3

How do I resolve this problem?

Thanks for your inpput