An engineer is attempting to establish a new site-to site VPN connection.
The tunnel terminates on an ASA 5506-X which is behind an ASA 5515-x.
The engineer notices that the tunnel is not establishing.
Which option is a potential cause?
A. Certificates were not configured
B. Diffie -Helman Group is not set
C. Access lists were not applied
D. NAT – traversal is not configured