如题，这几天不知道为什么，
每次在家打开医图网站就会显示下列的讯息，然后就无法连入。
The requested URL could not be retrieved
While trying to retrieve the URL: http://ntuml.mc.ntu.edu.tw/
The following error was encountered:
Unable to determine IP address from host name for ntuml.mc.ntu.edu.tw
The dnsserver returned:
No DNS records
This means that:
The cache was not able to resolve the hostname presented in the URL.
Check if the address is correct.
Your cache administrator is webmaster.
这种状况不管是否有用Proxy连线皆会如此显示，想请问这是什么原因？