To help with optimal game play and reduction of flash based issues such as white screens, Gray Circle of Death, Puzzle Piece errors, and other issues, please try some of the steps below to improve your computer's management of Flash:
First, Visit this Adobe Flash page to view information on your computer's Flash Player. Definitely always run the most recent version of Flash. The website I linked will help you determine that.
Additionally, ensure you are only running one version of Flash by checking your active plugins in your browser. If you are running more than one, disable all except the one that is most current.
If you run Chrome, try disabling PepperFlash.
Clear your Flash cache: To do this, close all browser windows. If you're using a PC, open your Control Panel; if you're using a Mac, open your System Preferences. Click the "Flash Player" icon to open the menu. In the menu, select the "Storage" tab across the top and click the "Delete All" button. In the window that pops up, ensure that "Delete All Data and Settings" is checked and then click "Delete Data."
Lastly, try increasing your local Flash storage: To do this, first open War Commander. From there, right click on the game screen and select "Settings." Then find the "Local Storage" tab, which is marked by a folder icon. In the "Settings" window, increase the available memory to "Unlimited."