Why my PC cannot login WVPN Client tool?

If the account and password is input correctly, but the WVPN main interface doesn't pop up. We can do steps as follows:

1. Right click the Internet access icon on the Windows taskbar;

2. Open Network & Internet settings;

3. Change adapter options;

4. Just reserve the options of adapter of WVPN (TAP-Windows Adapter V9) and necessary Internet connection, then disable all others options.

5. Try to login the WVPN tool again;