Undefined list in phaser.js

Hello, I’m really new to game developping and I’m following a tutorial series on Youtube. I have the exact same code as the video, but I keep having this error showing up in the console log of the browser:

TypeError: list is undefined phaser.js:76711:9

I’m not really sure if my code has something to do with it ? If you can help me and need the code, I’ll be glad to post it ! Thank you !

Have you checked the version you are running?