Hello William Gao1,
Thank you for posting in Microsoft Community forum.
Based on the description, it seems your machine is in your organization network.
If you are sure your PIN function is disabled by your organization, the best and quickest way to resolve this issue is to contact your university's IT support or help desk. They have the authority and tools to reset your PIN or enable the PIN function.
I hope the information above is helpful.
If you have any question or concern, please feel free to let us know.
Best Regards,
Daisy Zhou