In your smartphone, the window can popup anytime and you can just input your name and password. But the router is another device. I don’t know where the window can pop up if you don’t use the browser.

Of course, we can ask the user to start the openvpn manually each time from the UI, when he need to type the password again. But most people will go crazy. The openvpn connection can drop any time because of some issues. It will always try to reconnect. Without remembering the username and password, it cannot keep the connection.

Maybe there is some easy way to do this. I will research on this.