your hardware might be incompatible NOTE: Not all mobile devices/operating systems currently have the required hardware/software to run the Look extension used in this unit. Please check here to see if your mobile device is on our list of devices where the extension is known to work. If your device is not on the list, we highly recommend testing beforehand to make sure it is compatible.
Chromebook a Chromebook, as most will support the LookExtension. In addition, many Chromebooks now support running Android apps, so the MIT AI2 Companion can be installed directly on the Chromebook, and students can run the App Inventor IDE and the AI2 Companion on the same machine.
Train. Yes you have to train it. Train a Model with the Personal Image Classifier
Students open Web browsers on their computers and use http://classifier.appinventor.mit.edu/oldpic/ to create a model of different facial expressions.
If you have not trained the PIC might be the reason
I don't have a Chromebook .
I can tell you the advice to use the Look extension does work on my Android 8.1 Samsung tablet. A guess is it might not work on your redmi because of hardware issues or not training . Since you haven't trained, you may have to do that to get either your redmi or chromebook to work.
Train the software and try again?