Clear your DNS cache

If you cannot access the system, pelase clear your DNS cache. 
To clear your DNS cache if you use Windows, perform the following steps:

Click Start.

Enter cmd in the Start menu search text box.

Right-click Command Prompt and select Run as Administrator.

Run the following command : ipconfig /flushdns.

If the command succeeds, the system returns the following message: 
Windows IP configuration successfully flushed the DNS Resolver Cache.