Try going into your device's Settings >> Application manager and find the CNN app in the list. Tap on it, tap on the 'Force stop' button, then the 'Clear cache' button. Now see if the app is working OK again. If it's still not displaying new content properly, go through the previous steps again but instead tap the 'Clear data' button instead of the cache button. This wipes the app's settings and its cache, essentially returning to its original, just-installed state (if the CNN app required an account login, by 'Clearing data' you'll need to re-enter your CNN user name/password.)