Have you seen this screen whenever you tried to load one of your own websites in the browser?
So what causes this and how to fix it?
Technically this error comes up when the HTTP service is not running on the server (in this case ‘localhost’). HTTP request are served through the HTTP service which usually runs on port 80 of the server. If your web server (i.e. Apache) is not started, the port 80 won’t be able to serve incoming HTTP requests and as a result you may get this error. So basically what you have to do is first check and make sure if the Apache service has started. If it is already started but you still see this error it is possible that the server may not be functioning properly due to some other issue. Possibly in its configuration. In that case you have to find and fix the error and finally restart the server to see if it is getting resolved.