422 Unprocessable Entity

The server understands the content type of the request entity (hence a 415 Unsupported Media Type status code is inappropriate), and the syntax of the request entity is correct (thus a 400 Bad Request status code is inappropriate) but was unable to process the contained instructions.

For example, this error condition may occur if an XML request body contains well-formed (i.e., syntactically correct), but semantically erroneous, XML instructions.

Source: RFC4918 Section 11.2

422 Code References

.NET HTTP Status Enum HttpStatusCode.UnprocessableEntity
Rust HTTP Status Constant http::StatusCode::UNPROCESSABLE_ENTITY
Rails HTTP Status Symbol :unprocessable_entity
Go HTTP Status Constant http.StatusUnprocessableEntity
Symfony HTTP Status Constant Response::HTTP_UNPROCESSABLE_ENTITY