Function redeem_next 

pub(crate) fn redeem_next(body: &str) -> String

The repair for a refused redemption, worked out from the node’s message.

Reads the error string because this endpoint has no rejection code to branch on. Substring matching is the weaker test and is used knowingly: the fallback is a true sentence for every message that does not match, so a reworded node message costs a specific line and never produces a wrong one.