Well, I feel like I’m unlucky…
I removed the images that show game covers.
Unfortunately I got refused again 
They don’t accept it due to copyrighted content again.
I feel like this is not the same “error” but I’m still lost, I don’t know what to provide in this situation 
For example, your app contains: images from popular video games within the App Experience.
The only thing that I’m using in my app are images provided by Twitch (Game covers, Stream previews and community images).
I still don’t understand what is the difference between my app and the other ones available.
Well, if you have more hints, I would take them!