New Active Directory Domain Services Connection

Hi charlie4872,

In your position, I would first look to see why this particular DC is no longer replicating to the others - are there network problems at the site, OS problems with the DC itself etc? If your not familiar, the Active Directory File replication tool is a handy GUI to identify replication issues between different domain controllers 

https://www.microsoft.com/en-us/download/details.aspx?id=30005

Alternatively, the repadmin cmd is also very powerful at getting at the problem of replication issues. 

https://docs.microsoft.com/en-us/previous-versions/windows/it-pro/windows-server-2012-R2-and-2012/cc770963(v=ws.11)

You can look at trying to add new sites and get DC's to try and reach the problem DC, but I tend to find it better to get to the root cause rather than add more moving parts to the mix.

Hope this helps,

Mark