Which API endpoint are you trying to use to fetch the license details?
Are you invoking the API from your application or backend server?
Personal access token must not be exposed in any app which you deliver to your customer.
If you are invoking the API from backend server, then you can get license details using following:
with productId and email query params.
In case you want this information in the client app, then your user must first login using the following endpoint:
This will return an access token for the user, and then you can invoke following endpoint to get the license details from your frontend app or desktop app: