I had the issue for weeks. With help from google, I restarted the cam
with the little button on the back of the cam, for more than 12 seconds.
(I tried 10...) then a sound and a blue light and I was able to install.
Not using the QR code but the code...
I have the same problem. Google send me a new cam. Still the same
problem. So it is not the cam. Am using iPhone 11 max pro. Other cams
(indoor) and google products have no problems.