Domain Cached Credentials Lost After Resume From Hibernate

My boss is working out of town and he was logging into his laptop

using his domain cached credentials. This was working fine until his

laptop went into hibernation mode. After that, he tried to login with

the same password at the "Locked" screen and it is not allowing him.

I had this issue last week with someone else and we gave up until he

simply got back. When he plugged back into the network, he logged into

the domain and his credentials were once again cached properly.

What would cause this, and is there a way to fix my boss now? I'd love

it if he could get into his domain profile while away.

How can I prevent this from happening again? This seems to be a

recurring issue.

Thanks,

Derrick