@Sam1008787 

Hi,
On the Tapo app > camera's Live View page, please check if the Video mode is set to Auto. Typically, the camera will automatically switch between Day/Night mode according to the ambient light conditions when the Video mode is set to Auto mode. For example, if the camera does not switch to Night mode when it gets dark, it may be because the ambient light conditions do not reach the threshold for switching modes, and the camera may switch to Night mode in darker conditions.

In your case, please check the Video mode the camera uses and send us a picture of the camera's Live View page when the lights are all off.

Best Regards