We had some fun getting in touch with someone at Samsung who actually knew what we were talking about.
As such, hopefully this saves you all some time.
Password: sec00000 (that's 5 zeros)
The session setup from the computer %% failed to authenticate. The following error occurred: Access is denied.
Event ID: 5805
The session setup from the computer %computername% failed to authenticate. The following error occurred:
Access is denied.
We ran into a client with PCs that would not authenticate to his domain controllers.
After further investigations, the client had configured an RODC for a remote office and had not yet added the specific user or computer groups to the trusted list.
Just for those how are not aware, EVERY COMPUTER in a domain has an account (just like a user account, except it ends with $).
Add User & Computer Security Groups to the RODC Cache:
Active Directory Users & Computers -> Right Click -> Properties of the RODC -> Password Replication Policy -> Add
Choose the Computers individually or add the entire "Domain Computers" security group, or even better, create a new security group for the specific computers you would like this RODC to authenticate.
Once you've added them to the "allow" status in this window, reboot the PC and allow 15+ minutes for replication to the RODC to complete.