Constant ISSUANCE_PRECONDITION_FAILED 

pub const ISSUANCE_PRECONDITION_FAILED: &str = "issuance precondition failed";

Marker carried in the error chain when an issuance is refused because its precondition no longer holds - a renewal whose certificate was revoked while the renewal was in flight.

A stable substring rather than a typed error because it has to survive the anyhow chain and the JSON-RPC string that carries it to the client, which is the only place the distinction is actionable: the client must re-enroll rather than retry.