I’ve the same problem, my 4 Swann cameras randomly go grainy, at night time. I haven’t a clue what it is I’m so baffled. The only way I can clear it is turn the built in light on the off. But even that light flashes when I turn it on. Then the grainy picture clears. Very odd. I’d love to know how to permanently stop it going grainy & how to make the light turn on without flashing.
I had Hikvision cameras before these which were brilliant albeit more expensive but no issues whatever. I stupidly enough let my boyfriend change them as we were adding another camera & it worked out cheaper to replace with Swann. Wish I’d never agreed to it as this tends to pick up motion but then jump so I miss the bits I was hoping it would retain.