Many of my apps were downloaded from the Amazon AppStore as part of their "Free App of The Day" (henceforth FAoTD) program. This program was recently discontinued in favor of
Amazon Underground - an all-encompassing shopping app, similar to any number of their other shopping apps for Android. Since I was not interested in continuing with
Android Underground, I uninstalled the
Amazon App, AKA
Amazon Shopping, AKA
Amazon for Android apk.
The next time I tried to run one of the apps from Amazon from the FAoTD, I encountered a dialog and immediate shutdown of the app when acknowledged with the OK button:
Amazon Appstore Required
It looks like you no longer have an Amazon AppStore on your device. Please install an Amazon AppStore and sign in with your username and password to use this app.