Seems like I got a new error, when I do the full request to get the reward
https://api.twitch.tv/helix/channel_points/custom_rewards/redemptions?broadcaster_id=${broadcaster_id}&reward_id=${reward_id}&status=FULFILLED`
I got this error
error: 'Forbidden',
status: 403,
message: 'custom reward was created by a different client_id or channel points are not available for the broadcaster'
}