Why is my ringtone choice not saving on the Samsung galaxy 7?

[AC Question]

I have a new Samsung Galaxy 7, with software version Android 6.0.1. It has the ringtone set as Over the Horizon as default but will not let me change to another set in the phone. I can select any other one but it does not save it. Any way to fix this? Other settings such as in Sounds are saved ok.