Try going to the settings, and modifying it there. There is a setting for the push provider.
Discussion
Ntfy, Android or Amethyst settings?
Amethyst settings
Thanks, but "Notifications" is not visible under application settings or anywhere else in the app.
Running 0.80.2.
In Amethyst's settings, you should see Push Notification at the bottom. You can select Ntfy from there.