I have run dfsdiag /testdcs and I am getting the error:
Server has IP address with conflicting site associations
Now I think this is probably due to the fact that the server in question is linked to the others by a static VPN connection which gives it an ip address on the other network which is then confusing dfs.
Any ideas of what I have configured incorrectly?
Additional Info: Site1 has ip range 10.66.x.x and Site2 has 10.69.x.x but the server in site2 has an ip of 10.66.0.254 assigned by the VPN connection so it is thought of being in the wrong site
It is generally a good idea to keep the IP addresses used by VPN connections to a completely separate subnet or range of IP addresses. This will make it a lot easier to understand the routing decisions taken by the various hosts involved in the traffic.
Most VPN connections use a small tunnel (i.e. a subnet of 4 IP addresses), consisting of the network address, the 2 clients and a broadcast address. In your example, this could be something like 10.70.1.0/30.
Once you have that in place, you should be able to see (via traceroute or other means) where traffic is going and where it is dropped. That will then give you an idea of any missing route table entries, and should remove the confusion of dfs.