Cannot log into Windows 2012 Essentials with Administrador Account

I have a Windows 2012 Essentials server, it was running with no problem for more than a year,
Today I cannot access via RDC or physical with the administrator account,

I get this error: "The security database on the server does not have a computer account for this workstation trust relationship"

What can I do?
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ITSysTechSenior Systems AdministratorCommented:
I've see these issues if the server cannot see the domain. It is most likely a DNS issue. Could you look at your DNS Manager and make sure your server is there?
marpanetAuthor Commented:
Because it´s Essentials, the Server itself is the domain controller, I cannot log on to see what Dns is configured, but I am sure it has at itself as the DNS.
Lasse BodilsenSystem AdministratorCommented:
Can you login with a local admin account (if one was setup) instead of the domain admin account?.

"computername\admin" instead of "domain\administator"
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Shaun VermaakTechnical SpecialistCommented:
Do you have the DS recovery password? You can boot into DS recovery mode.

I always recommend adding as a DNS server for when the adapter fails

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marpanetAuthor Commented:
Sorry for the confusion....
Here´s the story update....
This company has two Essentials Servers on the same network (different companies), I was trying to log in into the server with  othercompanydomain\administrator

That´s why the error appeared.... changing to the correct domain didn´t work because someone changed the administrator password to something else.
ITSysTechSenior Systems AdministratorCommented:
I'm glad you got it figured out.
ITSysTechSenior Systems AdministratorCommented:
inactive for 14 days
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Windows Server 2012

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