If your Android device is not scanning a QR code, there could be a number of potential issues at play.

I have hp printer with scanner software which won't install properly. I also have paint program "from scanner or camera" is greyed out. I can't scan in paint. I spoke with HP tech support highest Tier ...

The first thing you may want to do is reset the printer scanner. This is a simple task, so we do not expect most users to find it too difficult. To reset the printer scanner, the user must power it ...