So i'm using rectangle light for this background (and similar errors occur in other places) , but it turned out not fully lighted. As you can see on the preview image below that the light only brighten the center area of what it should be doing is lighten the entire area as where i put the rectangle light (screenshot also attached). I have tried to replace it with a new rec light, tried to close and reopen the file, and tried restarting my pc, but still doesn't work. What's the issue here? And how can i fix it?
Thank you in advance!