@Tech Support, To let domain user to login using PIN, we need to firstly enable it. Here is a link describe the steps to enable it via group policy or regedit key for your reference:
https://www.tenforums.com/tutorials/80520-enable-disable-domain-users-sign-pin-windows-10-a.html
Note: non-Microsoft link just for the reference.
Hope the above information can help.
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