A systems administrator is setting up a new server that will be used as a DHCP server. The administrator installs the OS but is then unable to log on using Active Directory credentials. The administrator logs on using the local administrator account and verifies the server has the correct IP address, subnet mask, and default gateway. The administrator then gets on another server and can ping the new server. Which of the following is causing the issue?

A. Port 443 is not open on the firewall
B. The server is experiencing a downstream failure
C. The local hosts file is blank
D. The server is not joined to the domain