Did you ever experience a problem of proxy server refusing connection while browsing internet with Firefox or Chrome as shown in the picture below ?
Go to “Internet Options” and then click on “Connections” tab.
Since your computer doesn’t use a proxy server and if it is checked then your computer tries to connect to the internet through the Proxy server and you will run into the trouble.
After removing the tick mark from the check-box, click on “OK“.
This is how you can remove the proxy server problem while connecting to the internet.