Hello @Muhammad Tayyab ,
Thank you for posting here.
I have check in my lab, edit unicodePWD on the Properties of one user. And I have similar error as you.
After my research, it seems we can not edit unicodePWD via GUI.
Hope the following links is helpful to you.
Active Directory password change #92
https://github.com/ldapjs/node-ldapjs/issues/92
Update unicodepwd in ActiveDirectory
https://stackoverflow.com/questions/29624457/update-unicodepwd-in-activedirectory
Please note: Information posted in the given link is hosted by a third party. Microsoft does not guarantee the accuracy and effectiveness of information.
Hope the information above is helpful.
Should you have any question or concern, please feel free to let us know.
Best Regards,
Daisy Zhou
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