@Pity 

Hi,
1. What are your Tapo camera's model number, firmware, and hardware version?

2. Please check if the Video Mode is set to Auto on the camera's Live View page. If so, the camera will automatically switch between Day and Night modes according to the ambient light. Usually, the camera switches to Day mode during the day and displays a colorful screen, and it switches to Night mode at night and displays a white and black screen.

Currently, if the camera switches to night mode automatically at night and displays a white and black page, it means that the area around the camera is dark and the light is low at night. Even if you manually set the camera's Video mode to Day mode, you may still see a black screen on its Live View page rather than a colorful screen.

Best Regards