|To test domain logons, if having an issue from one machine, it to go to a known working machine and have them logon to the domain.|
If they can logon, its a local to the machine issue. If they can't its a domain account issue.
Not clear from your answer if you had them try to logon from different machines then the three problem ones.
You didn't state if these laptops/pc are members of the domain.
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