Check Channel Subscription by User is not respoding

API
2

The user 217377982 aka Sweet Anita does not subscribe to use 536156549 aka arnav1212

You have the ID’s the wrong way round, for the channels endpoint

https://api.twitch.tv/kraken/channels/STREAMER/subscriptions/USER

Or you do

https://api.twitch.tv/kraken/users/USER/subscriptions/STREAMER