Secure Channels problem

Can anybody give me an exlain on a problem I have. My company has a master domain model in place with one accounts domain and several resource domains. The problem is that for no apparent reason the secure channels from the servers in the resource domains to the servers in master domain become out of line causing authentication to happen over the WAN. When I go into Domain Monitor and reset the secure channels they still become out of line after a period even if none of the servers has been rebooted. This causing unecessary network traffic and nobody can give me an explanation. Help Please.