i am trying to dcpromo a DC from 2008 R2 and i keep getting an error stating the operation failed because it cant connect to another DC (2012 R2 machine). i have transferred roles succesfully, ran FSMO successfully, but old DC will not demote. i turn old DC off and active directory in new DC (2012 R2 ) machine stops functioning and all my users disappear. only when i turn on old DC does active directory begin to function correctly. any advice on what to do? DNS and DHCP is working correctly on new DC.