A short, human-readable summary of the problem type. It will not change from occurrence to occurrence of the problem, except for purposes of localization
You do not have enough credit
A URI reference [RFC3986] that identifies the problem type. This specification encourages that, when dereferenced, it provide human-readable documentation for the problem type (e.g., using HTML [W3C.REC-html5-20141028]). When this member is not present, its value is assumed to be "about:blank". It accepts relative URIs; this means that they must be resolved relative to the document's base URI, as per [RFC3986], Section 5.
NotEnoughMoney
A human-readable explanation specific to this occurrence of the problem.
Your current balance is 30, but that costs 50
A URI reference that identifies the specific occurrence of the problem. It may or may not yield further information if dereferenced. It accepts relative URIs; this means that they must be resolved relative to the document's base URI, as per [RFC3986], Section 5.
/account/12345/msgs/abc