http 422 Unprocessable Entity

4×× Client Error

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

Rails HTTP Status Symbol :unprocessable_entity
Symfony HTTP Status Constant Response::HTTP_UNPROCESSABLE_ENTITY