Hai,

In my office we have 64 systems. These are all in domain. The domain name is polyster.com. The problem is www.polyster.com and email.polyster.com is our website and our company mail. The problem is its not opening in domain controller systems and even in server also. But if the system is in workgroup its opening without any interuptions. But if it is in domain the website and email are not opening.
I am not at all understanding what is the problem. Please help me out this problem.

Check your DNS settings.

Do you have an authentication server that users log into?

I checked the dns settings and created host in dns and gave the ip address of website and email. Now its working