Zapping in Amethyst became a problem a few months ago. I think wallet compatibility in Lightning Network is messing up zaps.
Discussion
I suspect a bug in Amethyst. There shouldn’t be any wallet compatibility issues unless you’re doing something weird like Zeus.
After playing with multiple Nostr clients for Android in the past two weeks, I've seen where some clients I can hardly zap anyone, and others that appear to allow me to zap everyone (but with suspicious UI, so it's difficult to determine).
If LN and wallet compatibilty aren't at play, then implementations in Nostr are widely inconsistent, or not following LN rules properly, etc.
There’s many different layers where the problem could be happening for failed zaps so it’s hard to troubleshoot
