Sometimes, after installing Charles or any other web proxy on your Mac OS, Outline VPN or any other 3rd party client on your Mac OS can break your VPN connection. To fix it you need to:

1. Remove the web proxy configuration from the «Details» tab of your Wi-Fi network configuration.
2. Remove the web-proxy configuration from the VPN connection configuration.
3. If you don’t have VPN connection settings and are using a 3rd party client (e. g. Outline VPN), you will need to remove the VPN connection from the VPN tab in System Preferences (not in your client) and reconnect using the 3rd party client.
4. In this case the connection will be recreated in System Preferences without proxy settings.

Alternatively, you can manually remove the proxy server configuration from

/Library/Preferences/com.apple.networkextension.plist

using any plist editor (e. g. BBEdit) and restart your OS.