QR scanner not woking at all

Hi all,
I just installed plugin QR scanner and wanted to scan some QR code. But when I click on button, no camera preview is shown. Even if I set background to transparent like in this post: Ionic QR Code scan not opening camera for iOS and Android devices

In a console I do not have any errors :-/

Is this plugin not working at all?


send the plugin name

It is this plugin: https://ionicframework.com/docs/v3/native/qr-scanner/