How to Fix Firefox Proxy server is refusing connections Error?

The “The Proxy server is refusing connections” error prompt when Mozilla Firefox users try to access certain websites. This error occurred because the service is not letting the Firefox browser to forward the data. Follow below resolution steps to resolve “Proxy server is refusing connections” error.

Solution 1: Force Firefox to use Auto Detect Proxy Settings

1. Open the Mozilla Firefox browser.
2. Click on the action button in the top-right section of the screen.
3. Choose Options or Preferences from the context menu.
4. Select the General category from the vertical menu on the left.
5. Scroll down the right-hand side menu until Network Settings.
6. Click on the Settings button to open the advanced menu.
7. Set Configure Access to the internet to Auto-detect proxy settings for this network.
8. Click Ok to save the changes, then restart the Firefox browser.

Solution 2: Add URL SSL port to the allowed list

1. Analyze the URL that is triggering the error to check the port that is being actively used for HTTPS.
2. Open proxy configuration settings and look for a setting that will allow you to add the port as an alternate SSL port.
3. Save the configuration change and restart the computer.

Solution 3: Switch to HTTPS Proxy

If you are accessing FTP site through an HTTP proxy, make the switch to an HTTPS proxy that ensures communications with end-to-end security.

Solution 4.1: Disable built-in proxy server (Windows 10)

1. Press Windows key + R to open Run box.
2. Type ms-settings:network-proxy and press Enter to open the Proxy tab of the Settings menu.
3. Scroll down to the Manual Proxy setup section at the right-hand side menu.
4. Toggle OFF the Use a proxy server setting.
5. Restart the computer.

Solution 4.2: Disable built-in proxy server (Windows 7 and Windows 8.1)

1. Press Windows key + R to open a Run box.
2. Type inetcpl.cpl and press Enter to open the Internet Properties tab.
3. Select the Connections tab, then click on LAN Settings button under Local Area Network (LAN) settings.
4. Uncheck the Use a proxy server for your LAN setting.
5. Restart the computer.

Solution 5: Uninstall VPN Client

1. Press Windows key + R to open a Run box.
2. Type appwiz.cpl and press Enter to open the Programs and Features screen. If UAC (User Account Control) prompted, click Yes to grant administrative privileges.
3. Scroll down through the list of installed applications and locate the VPN client that you are using then right-click on it and choose Uninstall from the context menu.
4. Follow the on-screen prompts to complete the uninstallation, then restart the computer.