Use the following troubleshooting steps when running into Domain Replication issues. These will sometimes happen when replacing DC’s without going through the proper replacement steps which should be the following:
Add the new DC’s => Promote them.
Integrate them => Configure roles and services.
Take the originals offline => Keep them running side by side at least for 24 hours if possible.
NOTE: DHCP/DNS issues can usually be resolved by adding the IP as a secondary on the new servers NIC once you power the old server off.
On the domain controller, Run =>
eventvwr.msc=> Check the logs regarding Active Directory. If there are errors or warnings, try the following:
Type each of the commands and study their output:
1 2 3 4 5 6 7
repadmin /showrepl * /errorsonly >log.txt # see [this](https://technet.microsoft.com/en-us/library/cc770963.aspx) repadmin /replsummary repadmin /syncall dcdiag /c /e /v /q /f:results.txt # see [this](https://technet.microsoft.com/en-us/library/cc731968.aspx) netdiag /q /v /dcAccountEnum /l >>log.txt# see [this](https://technet.microsoft.com/en-us/library/cc731434.aspx)