VPN L2TP with AD accounts + Google Authenticator

Hi everybody,

I'm currently trying to configure remote access for a client on an ATP700. I chose to use L2TP and I wonder if it's possible to enable Active Directory authentication AND 2FA with Google Authenticator at the same time ?

If it's possible, how to configure 2FA for each client AD account ?

I found this procedure, but only SMS and mail are mentioned, not Google Authenticator :
https://support.zyxel.eu/hc/en-us/articles/360018775280-How-to-do-Two-Factor-Authentication-with-Active-Directory-Users

Is it possible or should I give up AD account or Google Authenticator ? 

Thank you