After wireless users connect to the wireless signal point, they can’t get it IP Address, what are the possible reasons ()? (Select 2 Answers)

After wireless users connect to the wireless signal point, they can’t get it IP Address, what are the possible reasons ()? (Select 2 Answers)
A . Where the user is VLAN No configuration DHCP server
B . wlan-ess No configuration on the virtual interface dhcp-enable
C . The authentication password specified by the user is incorrect
D . User equipment MAC The address has been added to the blacklist

Answer: A,B