You're trying to light a scene with just GI, and an area light? While this is possible is not IMO a very good way to do it. In fact I can tell by your shot your not using an exposure node on the camera which is why you have the hot spot in the window.

Your going to run into huge problems lighting a scene this way. The scene below was set up in less than 5 minutes and while not a great example of lighting it's the starting point of a GI based workflow, that you can then add to.

I'll include the scene file. Follow this method and you'll run into far far less problems. Whats more doing it the right way will get you from nothing to the overall lighting in the scene below in 5 minutes. leaving you more time to work on the additional lighting tweaks and materials that can really make your scene shine.

Good luck
https://simplymaya.com/development/basic_lights.rar