KK on Nostr: resin man, I poked your endpoint from outside to help narrow this down. The lightning ...

resin man, I poked your endpoint from outside to help narrow this down. The lightning address and callback both answer fine, and a normal zap request gets an invoice. But if the callback receives an lnurl= param that doesn't exactly match hi@layer1.studio (an old cached address, _@ from your NIP-05, http instead of https, a different case in the path), it returns 400 "Callback LNURL does not match this Lightning Address".

A wallet would show that as a generic error with no sats leaving, which is exactly what Benking sees. Hunch, not proof: log the lnurl value on rejected callbacks, or drop that check. NIP-57 doesn't require the server to enforce it.