Can't log in
If the user receives an error message saying their account is locked out, it will need to be unlocked in Active Directory before attempting again.
If the user receives an error message saying the domain can’t be reached, check that the network cable is plugged in at both ends. On some PCs, the network port gets disabled during sleep mode and doesn’t re-enable itself correctly. A hard reboot will usually fix this issue.
If the user receives an error message saying the trust relationship failed, it means the computer needs to be removed from and rejoined to the domain. You can use the local Administrator account to do this.