If you are building REST APIs you will understand that HTTP status codes at times are not sufficient to convey enough information about an error. There is a specification RFC 7807 that defines how you can return error information back to the client. The way it works is by identifying a specific type of problem with a URI.
To make it more clear let’s suppose you are building a todo list application where you want to build API to move items from one list to other. If the target list has a cap on maximum items it can hold and you try to move an item from source list to target list the list then you should get an exception.
If all you have is HTTP status code then you can just return HTTP status code 403 forbidden. However, it does not give the API client enough information about why the request was forbidden. Different developers have solved this problem differently by building their application specific error objects. Problem Details for HTTP APIs specification solves this problem by defining a standard format in which API error response should be returned.