Both error messages, ("The trust relationship between this workstation and the primary domain failed." and "There are currently no log on servers available to service the logon request")  are common reasons a MCS user may have trouble logging in.

Trust Relationship Issues happen at random while a computer is talking to a log on server.  For whatever reason, the server and the computer had a bad chat, and now the server doesn't trust the computer.  A user will need a helpdesk person to resolve it.  After it is resolved the computer should work as normal.  Computer trust issues have no known common cause and are experienced in many domain environments elsewhere.

No Log On Servers Available is a problem with the computer connecting to the network.  If you experience this issue with a desktop machine, please make sure your Ethernet cable is connected before sending in a ticket.  With a laptop, the wireless is often turned off or not functioning.  If you are a laptop user, it may be beneficial to try pressing the function key (the blue FN)  with the wireless key (the blue tower or orb with the the wireless waves emitting from it/ found on the the top row of keys). Then wait about 30 seconds to let it connect to the wifi.  Pressing those keys toggles the wireless on and off on a laptop.  If this fix doesn't work or you are experiencing trouble implementing them, please send helpdesk a ticket.