Proof of Possession Invalid¶

Type URI: https://usp-protocol.dev/errors/pop-proof-invalid

The proof failed to parse or verify: a bad typ, a rejected alg, a signature failure, or a mismatched htm/htu, usp_m/aud/usp_p, or ath.

Servers use this URI as the type member of an RFC 9457 Problem Details response. Clients must branch on the exact URI, not the human-readable title.