We lost a domain controller last week which caused us lots of problems but most of them are now resolved except we have a number of users who connect via VPN who cannot access any file shares on the servers.
When they try to connect to a share, it prompts for a username and password with a message to say "The system detected a possible attempt to compromise security. Please ensure that you can contact the server that authenticated you"
I suspect the problem relates to the subnet that the VPN users are coming from as when the user plugs directly into the LAN, the computer works perfectly, but I can't prove my theory as neither the client nor the server log any errors that I can see.
The domain controller that went down also served as a DNS server and I'm not sure that is working correctly but any suggestions for troubleshooting this problem greatly received!