When you change your password for the network, you may start seeing issues with your VPN connection. The most likely reason is that it has saved incorrect credentials. Please see below a simple guide on how to clear your credentials and reenter the correct credentials.
1. Type "VPN" in the windows 10 search bar
2. Click "VPN settings"
3. On the VPN profile select "advanced"
4. Then click clear credentials. And try again.