A FortiGate unit is configured to receive push updates from the FortiGuard Distribution Network, however, updates are not being received. Which of the following statements are possible reasons for this? (Select all that apply.)
A. The external facing interface of the FortiGate unit is configured to use DHCP.
B. The FortiGate unit has not been registered.
C. There is a NAT device between the FortiGate unit and the FortiGuard Distribution Network and no override push IP is configured.
D. The FortiGate unit is in Transparent mode which does not support push updates.