Frequently, this problem occurs when: use of DotVPN is blocked within the current network, the computer is infected with a virus or have been previously exposed to virus attacks. If the DotVPN is blocked in the network (the most common case), we can not help because it depends on your system administrator. Malware and Adware are the threat source to your computer, these programs often change your browser settings. Even after the delete of virus from the computer, the "Unable to connect to the proxy server" problem may remain. The code of this error — ERR_PROXY_CONNECTION_FAILED.

You will need to fix this error by yourself. Do not worry, it's not difficult at all!
- First you have to open Google Chrome and click on "Customize and control Google Chrome" (Three horizontal lines icon) and click on Setting.
- Now you are in Setting panel of Google Chrome, Scroll down to the bottom of the webpage, and click on "Show Advanced Settings".
- Now in Network, click on the "Change proxy Settings" option or open it.
- This will open new windows which is called Internet Properties, go to the Connection tab and click the LAN settings button.
- You will see a new windows again which is called Local Area Network (LAN) Setting. This is the main step of this problem and you need to do very perfectly.
- Under the Proxy server section, please remove the check mark from Use a proxy server for your LAN (These settings will not apply to dial-up or VPN connections) and Under the Automatic configuration check mark in Automatically detect settings and click OK.

Close the rest of the windows, Disconnect and reconnect your internet connection.

From this way may solve ERR_PROXY_CONNECTION_FAILED error. If you have any questions about it, please do not hesitate to contact support: support@dotvpn.com.

If you want see a video, try this: https://www.youtube.com/watch?v=wIQHCxAzD4Y.