If your domain is registered on NameCheap.com, you should follow this tutorial to update the NameServer of your Domain to our NameServer.
1. Open the NameCheap.com website and click on "Sign in". It will show you a login form.
2. After a successful login, click on the "Menu" Link.
3. On the right side a new menu will open, you should click on "Manage Domains".
4. Click on the domain name you wish to change.
5. Click on "Transfer DNS to Webhost" (You can find this under the "General" section in the left hand side of the screen.)
6. Select the "Specify Custom DNS Servers (Your own DNS Servers)" option and enter the nameservers accordingly.
Note: It may take anywhere from 12 to 24 hours for the changes to take effect worldwide.