Sonic Wall L2TP VPN - Cannot resolve internal DNS queries

Hello community!

I'm facing an annoying issue trying to provide seamless VPN network navigation using L2TP under IPSec with one Sonic Wall TZ500.

Our internal DNS queries simply won't work.

Here are my setup in Sonic Wall running SonicOS Enhanced 6.5.4.4-44n:

1 - All VPN services are enabled.
2 - L2TP server is enabled.
3 - WANGroupVPN is enabled.
4 - Network = DNS Settings

5 - VPN = Advanced = DNS settings for VPN

6 - VPN = L2TP ServerI really appreciate someone experience here.

Thank you!