I had migrated from Windows 2008 server to Windows 2012 server recently. Windows 2008 server was the DHCP server and I transferred the same to new 2012 server. But 2012 server was not leasing the IP's. I then noticed the events like 1046 and 1056 in 2012 server and gave DNS credentials commands. I tried unauthorising Windows 2008 DHCP and remove the role from 2008 server but from 2012 IP's were not leasing. I then transferred the same back to 2008 server and it started working.
I would like to know why 2012 server was not leasing the IP's and errors like 1046 and 1056 were occurring.