Ntfy is borked in the current version. Sending a new one right now.
Discussion
Test 0.90.3 that just went out
How do i enable ntfy/nextpush on amethyst again? I cant find the menu option
Settings, on the left drawer. Make sure to make a UnifiedPush service installed, like NTFY
Here?

Ohh you need to install the Fdroid version of amethyst. The one you are using uses the Playstore to send notifications