A 401 indicates that you don’t have permission to access the requested channel_id’s subscribers. You can check the body response for more information
You need a token with the relevant oAuth scope applied to it
The scope for this subscriber end point is channel_subscriptions
Scopes are noted here: https://dev.twitch.tv/docs/authentication/#scopes
Authentication here: https://dev.twitch.tv/docs/authentication/#getting-tokens
Channel Subscribers here: https://dev.twitch.tv/docs/v5/reference/channels/#get-channel-subscribers
Authentication
Required scope: channel_subscriptions
URL
GET https://api.twitch.tv/kraken/channels/<channel ID>/subscriptions