Ultimate Predator Calls funktioniert nicht

These quality sounds are custom made, hand recorded sets from predator hunting enthusiast and author Douglas Boze. Why these select sounds?  The App supports the use of a bluetooth speaker (if you have one) to play the Sets at a distance from your location in addition to using the speakers on your phone directly.  Ultimate Predator Calls can help you call predators and other animals to your location.  When upgraded through an in-app purchase, you will have access to all 25+ minutes of high quality audio recordings, with the ability to loop any individual Set indefinitely.  The App features fourteen unique custom call Sets.  These calls are not generic sound bites like those found on other apps.  Pick your favorite background image to customize the App from 5 pre-selected images taken in the field.  They have worked for Douglas in Alaska, Idaho, Montana, Wyoming and Washington.  We are pretty confident they will work for you too!  Supports a 'dark mode' that will reduce the brightness of the screen, reducing any light pollution that might otherwise be a problem in a low light situation.