The specified DHCP client is not a reserved client.
Stand-alone DHCP servers are not allowed to operate when Active Directory is operating. This is to prevent unauthorized servers operating on the network. A DHCP server initializes and starts providing DHCP services to clients only if the server finds its IP address in the authorized list for each of the enterprise roots reported by other DHCP servers. If it does not find itself in the authorized list for each of the reported enterprise roots, it does not initialize and the DHCP service is stopped.
Verify whether the DHCP server is supposed to be part of a directory service enterprise or operating as a stand-alone server. If the DHCP server should belong to a directory service enterprise, reconfigure the server to be a domain controller or member server of the directory service enterprise, as applicable.