We need more information than what you have given us. Please do the following.
1. Describe your problem in detail
2. Describe what you are trying to do in detail.
3. Use good English. (And if English is hard for you, tell us.)
1. Malware. A possible problem, IF you do actually have a proxy server, is malware. Malwares are bad programs that disrupt the normal functions of your computer. They can bring physical and internal harm to your computer. There are lots of anti-malware programs but the best free one is Malwarebytes. Malwarebytes has pros and cons. The pro is that it will scan your entire computer and remove malware. The 2 major cons are that it isn't very effective against viruses, and it there is a 5 in 10 chance it will give you the blue screen of death. So my recommendation is to install it, scan and remove the possible malware infection, and then immediately uninstall it.
2. AddBlock Plus (From sertex)
"Try what I did, after installing Adblock plus I got the same error, so checking the setting for the extension I found × Enabled EasyPrivacy I unchecked and it works fine after restarting the browser."
3. Check if you are using a proxy server.
Select “Internet Options.” Click the “Connections” tab in the Internet Options window. Click the “LAN Settings” button. If there is a check mark in the box next to the “Us a proxy server for your LAN” option, then your PC accesses the Web through a proxy server.
This is all I could find/think of from the limited information you gave me. As I said before, describe your problem in detail, describe what you are trying to do in detail, and use good English. Then maybe I will be able to pinpoint your problem.