Sure but in the API you can ONLY talk to rewards that your clientID created
The problem you are having is that the reward you are trying to talk to was created in the dashboard (or another clientID)
You cannot manage dashboard created custom rewards (including fetching redemptions) via the API
EventSub (and pubsub) however, will notify of all custom rewards.
Then either
- use EventSub
- use PubSub
- Use your ClientID to create the reward instead - Reference | Twitch Developers
Then murilo_rt will use yoru App to create the rewards.
Or
You use EventSub or PubSub to consume redeems in real time.