Unable to register Windows 10 device to Azure AD.

Hello Experts. I have a strange issue. We have on-prem AD domain with .local, and have Office 365 subscription with .com domain. users have 2 identities, one for on-prem, the other for cloud. we leverage E-mail, Sharepoint, SFB...in O365. When a few users try to activate Office Client on their local domain joined machines, the devices registration fails with the attached error pic: Capture. And in event viewer, i see the error in: pic2. We are not leveraging Microsoft Intune, or any other type of MDM, or KMS. Has anyone experienced this issue? Any guidance would really help. Thanks in advance.
Newguy 123Asked:
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Newguy 123Author Commented:
I have already tried to un-install and reinstall the office client from the users O365 portal, remove cached activation keys from the computer, and un-license, and re-license the user in O365...but no luck as of yet. still facing same issue.
how you are trying to activate Office 365 software?

from software console itself?

User should have O365 Proplus license in order to activate the product

There is been never requirement that device must be registered in order to activate office

what setup do you have?

I believe you have standalone O365 tenant. Correct?

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