To interact with Twitch you need to create an application in twitch developer console.
Create a Twitch Application in the developer console
https://dev.twitch.tv/console/apps
Add following redirect URLs to you Twitch Application
https://{YOUR_URL}/connection/callback
https://{YOUR_URL}/connection/app-token/callback
https://{YOUR_URL}/connection/bot/callback
All domains need a valid SSL certificate.
Copy Client ID to TWITCH_CLIENT_ID
TWITCH_CLIENT_ID="{Client ID}"
Copy Client Secret to TWITCH_CLIENT_SECRET
TWITCH_CLIENT_SECRET="{Client Secret}"
Click "New Secret" to generate your first client secret