Http error: 422 – Unprocessable Entity
The 422 (Unprocessable Entity) status code means that the server cannot understand the content of the request. This is generally caused by incorrect syntax in the request.
For example, a common cause of this error is when someone tries to submit a form with invalid data. The server will be unable to process the form and will return a 422 status code.
If you receive a 422 error, it is usually due to a syntax error in the request. To fix this, check the syntax of the request and make sure that all required parameters are included.
RFC #: 4918 Section 11.2