Amazon Prime video app will download but not install

[AC Question]

I've got an HTC One M9 and I've downloaded both from the Amazon Underground App as well as the apk, unknown sources are allowed. For some reason it will allow me to download but not install. And error message pops up when the installation process is disrupted.

 

[B. Diddy]

Welcome to Android Central! What does the error message say? Do you have any other security apps installed?