(1) We have a 2012R2 root domain called company.us (NetBIOS = COMPANY_US)
(2) We installed a 2012R2 first child domain called resources.company.us (NetBIOS = RESOURCES) and this was successfully.
(3) I then go to install a 3rd 2012R2 child domain called users.company.us (NetBIOS = COMPANY) and this fails during replication.
CN=COMPANY,CN=Partitions,CN=Configuration,DC=Company,DC=us. Check the event log fro possible system errors.
"An Attempt was made to add an object to the directory with a name that is already in use."
So I ran NTDSUTIL.exe on the root parent > there is no sites or domains other than (1 - company.us) & (2 - resources.company.us) above. So there is no metadata to cleanup that i'm seeing.
Ping works from users.company.us to company.us.
IP is static
DNS is set to look at root.
Any insight or did I lose you yet ?