I mounted my camera on the back wall of the garage, about 22 feet away.
I could not get it to calibrate even when it was well lit. 22 feet is beyond the recommended range, but I didn’t want to move it
I solved the problem by Xeroxing the QR code sticker and enlarging it by about 50%, then taping that to the wall. It was the equivalent of moving the camera about 7 feet closer to the garage door.
Now it works fine.
I wonder if some people having intermittent problems with their garage door have it just barely in range for the camera to read the QR code. Remember when it is dark, the camera effectively has less resolution as well.
I just used paper and tape, but I am thinking of going to Office Depot or other print shop and have them print the larger code on sticker paper for a more permanent solution. If they don’t have sticker paper in 11x17, cut a copy of the QR in half, print each on 8.5x11, and cut them to overlap into one image