Check for valid RFC. If RFC is not found then validRFC field will be false.
rfcMessageCode gives the machine-readable reason for the outcome. RFC_VALID is the only value for which validRFC is true. RFC_PROVIDER_UNAVAILABLE means the RFC could NOT be checked — the provider failed — and must not be treated as a negative verdict on the RFC. The full catalog is RFC_VALID, RFC_VALID_NOT_INVOICEABLE, RFC_NOT_FOUND, RFC_FORMAT_INVALID, RFC_PROVIDER_UNAVAILABLE, RFC_UNKNOWN.
A malformed RFC supplied by the caller is rejected with HTTP 400 before any provider call, so RFC_FORMAT_INVALID is not returned on this endpoint — see the 400 example below.
status, message and errorMessage are unchanged; rfcMessageCode, and messageCode/rfcType on the error path, are additive.