By night, my outdoor camera is very dark in the background while the foreground is very bright

Example : 

According to some models, this phenomenon appears when a wall or something bright is in the foreground of the image.

At night, the IR LEDs come to focus on the wall in the foreground and prevent viewing in the background. it's all the more amplified when it's represent 1/3 of your image.

Therefore,  there is no other solution than to physically reorient the camera so that it visualizes the wall in the foreground as little as possible.

After reorientation :