@Solla-topee 

Hi,

Following are my remarks on your question.

1. On the camera's Live View page on the Tapo app, have you selected the Auto in the Video Mode, and is the Light icon in blue color which means the spotlight is on?

--- I have checked with by stand front of the camera and switched off the spotlight. Also tried by set the manual mode by night and day. But still no change. I was perfectly working from last 1 year on same place.
2. Please go to the camera's Device Settings>Video & Display>Night Mode Settings page to check the mode you have selected.

--- I have checked it by change all modes. Night, Day and Auto (Previously it was working on Auto mode perfectly)
3. The scene in the attached picture does not look like the camera's spotlight is on, but like there is a light directly to the camera lens. It is recommended to check whether there are other light sources around the camera.

--- No, there is no light source is on that time. Which we turn off all lights in night and there is full of dark.

I feel recently i was updated the firmware. I think your last firmware have any issue. How can i move to previous version.

  @NguyenKhoi 

@Solla-topee it's the reflection of the C320 spotlights, looks like there's something like a metal object is in front of the cam's view, you still can see in the background except that bright thing, which means the C320 spotlights are on.

--- I think there is no metal object. Also if any light source is not on there how reflection will came. I will do one think today night. I will take a another picture of video and settings i have in application and then will share with you. 

  @rsiwal generally something is in front of your camera.