If the window appears too white and/or overly bright in the rendering image, it could be due to the exposure value of the background.
To adjust this, click on the Background button in the Navigation Ribbon and reduce the Exposure Value (EV) using the slider.
For a daytime exterior, we recommend setting the exposure value between 9 and 10.5.
Confirm the changes by clicking OK and try running a new rendering. If the adjustment is correct, you should be able to see the background outside the window.
If not, repeat the procedure and adjust the parameter again.