I recently tried setting up a new camera using an Android device, and it wouldn’t read the QR code. I went to my iPhone, and it read it instantly, and then I noticed that the new version of the app, on the Android, was blocking part of the QR code, so the camera couldn’t see the full square (all three marked corners). I haven’t tried the Android again (yet), but perhaps that’s why it wouldn’t read the QR code for you.
I did ultimately notice that I could move the QR code on the android screen, and then all was in view, it just seems that the Apple version of the app sizes it to fit the space, whereas the Android version does not.