Hello Mercen,
Thank you for reaching out to Microsoft Support!
The subscription function varies from account to account, and for personal accounts, you can subscribe to the root folder or any subfolder in that drive. On OneDrive for Business, you can subscribe to only the root folder. You can see the details of this document:
Subscribe to Resource Path You can view this document:
For an error when you create a subscription, if you are using a work or school account, this error is expected.
Hope this helps.
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