Bharat,
I'm still confused. I have no idea what you mean when you say "port 993". Are you on another planet?You might as well be speaking Latin. I talked with my IT folk and they say that Mail should not be using "IMAP" to connect to our Exchange. It should be using "Active Synch". It should not be prompting for a certificate either.
So, how do I fix it? please state things in plain English as I have no idea what you're talking about. All I want to do is get our Exchange mail application to work with my Windows Surface tablet I bought. Occur Exchange works with iPhones, iPads, Android Jelly Bean, Macs, and all the other devices. But it does not work with your own surface device.