400 - Validation Error
Tip
The validation_error code is a general "top-level" error code returned when there was a validation error with your request.
A "validation error" essentially means that at least one property in your request has an invalid value.
The details of the response will provide more information relating to which property (or properties) failed validation. Each "child" error will include a more specific error code to allow you to pinpoint and resolve issues more easily.