I had a few of these cameras in the past. Actually still have one of them running.. The frame rates are not good on them, in particular in the nights. It seemed in my case that when the frame rate dropped to the 2ish and under range that
blue iris dropped the image, but at the same time, the web interface still showed a valid image. If I added light to the image the frame rate increased and the image came back in Blue Iris. This mainly happened at night in my case.