Difference Between "Trust Relationship..." and "No logon Server..."

There is a major difference between the "The trust relationship between this workstation and the primary domain failed" and "There are currently no logon servers available to service the logon request". Most of the time people think the both errors are coming when the computer is removed from the Domain. It is completely wrong and the both errors have their own possible cause to show that.

 The trust relationship between this workstation and the primary domain failed.

• Administrator removed from the AD.
• Last 30 days not synchronizing with the AD (This is vary from the 30 days to 3 month).
• Network failure.
• Power failure.
• System restores
• Windows issue
• Windows updates issue

There are currently no logon servers available to service the logon request

• This issue came only through the not having the connection between PC and the Ad either no network or a WiFi in a domain environment. 
• If the other user need to logon to PC, make sure have the network or WiFi in the domain environment. If you have the internet but not in a domain environment you can't login and you end-up with the above error.
• If the user previously login to that PC, but if user end-up with the above error in not connection with domain environment,
• User change their password after login to that PC and after that never login to that PC.
• That mean computer is identified the user is change their password but not logon to that PC. 
• User profile crash.