Help, from the person who wrote it.

One of three things, and by design the link can't tell you which: the note was already viewed its allowed number of times, it passed its expiry, or the link was never valid. If it matters, create a fresh note — the Sent tab on your phone shows what actually happened to the original.

Open the Sent tab and burn the note. The ciphertext is deleted from the server immediately; anyone opening the link afterwards sees only that the note is unavailable.

No. Passphrase attempts happen entirely in their browser and never consume views. Once they have the right passphrase from you, the note opens normally — as long as it hasn't expired in the meantime.

Every note keeps its own schedule: it still burns on its last view and still expires on time. What you lose is management — the Sent tab's status and early-burn button existed only on that phone, and there is no account to recover them through.

Receipts only exist if you switched them on for that note before creating it. If you did, check that notifications are allowed for BurnPony — the push is a generic "A note was opened." Opening the Sent tab always shows the recorded receipt times regardless of push delivery.

No. BurnPony is one-way by design — a note, not a conversation. If you need an ongoing encrypted thread, that's what CarrierPony is for.

No. Recipients need any modern browser on any device. Only creating notes requires the iOS app.

The app supports it today: Settings accepts a custom server URL, and each note remembers which server it lives on. The relay's source code is planned for public release; until then there's no public repo to deploy from — the roadmap tracks this honestly.