If you can see a message similar to the following, or you just can’t connect to the Internet, here’s a checklist to help you diagnose the problem.
Internet Explorer for Windows
Safari for Mac
After each of the following steps, check again to see if you can connect to the Internet.
Try to connect to another web site. If you can't connect to any other site, go straight to step 2. If you can connect to other web sites, then the problem is with the particular web site that returned the error message. Double check that you have spelt the web address correctly,then click Why can’t I connect to a particular web site?