b. My camera is not switching between day (color) and night (B/W).

Answer:

There are several issues that could be preventing your camera from switching between day and night mode.

1. Check your camera’s IR Cut Mode to ensure that the camera is not set to force either color or black and white and also that there is no schedule that prevents the change.
2. It is possible that the difference in ambient light between night and day is not enough. To solve this, also under IR Cut Mode, adjust the sensitivity to a higher value.