The box indicating that this domain controller is the last controller for the domain is unchecked. However, no other Active Directory domain controllers for that domain can be contacted

Question

I have 2 domain controllers running 2003 server, server1 and server2. I ran dcpromo on server1 and removed AD and removed him from the domain and disconnected from network. I then added a 2012 server
with the same name and IP address server1 with no problem. Replication from sites and services work fine on both controllers.
The new 2012 server1 is GC. I transferred all FSMO roles to server1. Again no problem and replicating using sites and services. AD on server1 is populated correctly.
Now what I had intended on doing was a dcpromo to remove server2 from the domain so I can then add another 2012 server. That is when I get the: "The box indicating that this domain controller is the last controller for the domain
 is unchecked. However, no other Active Directory domain controllers for that domain can be contacted.
I have DNS installed on both servers and both look good with replicating there. Strange thing is when on the 2012 server within DNS if I right click and connect to another DNS server I can add server2 just fine but from server2 adding server1 it tells me it
is not available.
Help please!

Answer 1

Hi,
As there is server 2012 DC (SERVER1) DC is operational in a domain then "This domain controller is the last controller for the domain" should be remain unchecked when you demote SERVER2 DC. 
If you are getting error "Active Directory domain controllers for that domain can be contacted" while demoting SERVER2 DC then check the DNS pointing on both as per below article, disable windows firewall on all DC, less possiblities but worth to check if both
are different site then check the ports are open on firewall. 
http://abhijitw.wordpress.com/2012/03/03/best-practices-for-dns-client-settings-on-domain-controller/
http://technet.microsoft.com/en-us/library/cc766337(v=ws.10).aspx
http://social.technet.microsoft.com/wiki/contents/articles/584.active-directory-replication-over-firewalls.aspx
run “ipconfig /flushdns & ipconfig /registerdns“, restart DNS server and NETLOGON service on each DC and try to demote server2 DC.
If issue reoccurs, post dcdiag /q result.
NOTE: If initial replication was completed between both DC (new 2012 and old DC) then you may remove the server2 DC from Active Directory forcefully (DCPROMO /FORCEREMOVAL) and perform metadata cleanup.
Active Directory Metadata Cleanup
http://abhijitw.wordpress.com/2012/03/03/active-directory-metadata-cleanup/
Best regards,
Abhijit Waikar.
MCSA | MCSA:Messaging | MCITP:SA | MCC:2012
Blog: http://abhijitw.wordpress.com
Disclaimer: This posting is provided "AS IS" with no warranties or guarantees and confers no rights.