Twitch TV api stream results shows null after sometime

As per intermediate project requirement I was doing this project.
I notice that whenever I add a new channel name in my array
var channels=["freecodecamp","jaidefinichon","whatthefoole","ilyon_"];
stream information shows fine but after using the project or api call for bunch of time… the stream result comes null .

I wonder is there any problem with my code or its Api security issue with Twitch Tv?