Extra +

Line
link="https://api.twitch.tv/helix/subscriptions/user?broadcaster_id="+streamer+"&user_id=+"+user_id
should be
link="https://api.twitch.tv/helix/subscriptions/user?broadcaster_id="+streamer+"&user_id="+user_id
Extra +

Line
link="https://api.twitch.tv/helix/subscriptions/user?broadcaster_id="+streamer+"&user_id=+"+user_id
should be
link="https://api.twitch.tv/helix/subscriptions/user?broadcaster_id="+streamer+"&user_id="+user_id