Also. it seems there is some issue with your API as well.
1. You just need to pass the subscription type only.
2. Need to use this API in the endpoint instead of component.
Below doc will help you
https://community.lithium.com/t5/Developer-Discussion/Board-subscription-option/m-p/409761#M13274
You can manage only your own subscription.
There is no such API to manage other user's subscription.
Is this still the case today? From what I've seen so far, you can only subscribe yourself to things, not other users.
I have a use case where I need to use the API to subscribe other users to various things, and am looking for a solution.
Currently this is not possible to add subscription for other user using API or other way. Only API available is for self subscription.
