That link is not live
One sentence for three cases: unknown, already used, and lapsed.
Both the guest payment link and the administrator invitation link answer with the same sentence, on purpose. Distinguishing "wrong" from "used" from "expired" would tell somebody guessing at links which guesses are getting warm.
So the three cases are:
- Unknown — the link was mistyped or truncated. Links break when they wrap in a chat message; send it again as one piece.
- Already used — an invitation works exactly once. If the password was set, sign in; if somebody else opened it, tell us.
- Lapsed — invitations last seven days and holds last as long as the hotel set.
The fix in all three cases is the same: issue a new one. Nobody, including us, can read an old link back — they are stored hashed — so there is nothing to re-send.