Malformed
The selected header did not match the expected t=<digits>, s=<base64> shape, the base64 payload failed to decode, or the signature bytes were rejected by the Ed25519 layer (e.g., wrong byte length).
The selected header did not match the expected t=<digits>, s=<base64> shape, the base64 payload failed to decode, or the signature bytes were rejected by the Ed25519 layer (e.g., wrong byte length).