Error logging into a Domain

Here is my situation and my problem. I have 2 locations, both several hours from each other. Both locations use the same domain name and the users going between the two use an assigned ip address, no dhcp. When the users first try to log into the domain they are unable, but if I disconnect the network cable log the user in and then reconnect the network cable then they are on the domain fine, no problems.

Any ideas how I can resolve this??