OpenVPN community edition with OTP and no OTP popup with Network Manager

Hi,
I am installing OpenVPN with PAM and OTP. Network Manager does not pop up a OTP window based on . Strangely when using OpenVPN AS (free) a OTP popup does appear. I have played around with various setting for OpenVPN and Network manager, for example:

Ovpn server config contains:

PAM: single password field containing Password+OTP

plugin /usr/lib64/openvpn/plugins/openvpn-plugin-auth-pam.so “openvpn login USERNAME password PASSWORD”

/etc/pam.d/openvpn contains:

auth requisite pam_unix.so nullok try_first_pass

auth required /usr/lib64/security/pam_google_authenticator.so
secret=/opt/openvpn/google-auth/${USER}
forward_pass
nullok
user=root
authtok_prompt=OTP

account required pam_unix.so

The Ovpn client config contains:

Only one prompt: password+OTP

auth-user-pass

Any ideas to get Network Manager to show the OPT popup welcome, including changes to the OVPN server (and related config).

Thanks

Hi,
Any updates or suggestions?
Thanks