REST service response error codes

Error Code	Exception	Description
400	Client Error/Bad Request (JAXBException)	The server cannot or will not process the request due to a client error. This usually occurs when the input xml is incorrect.
401	Unauthorized Access	Authentication is required to access a resource but has failed.
403	Forbidden (QuadrigaAccessException)	The user is trying to access a resource (project, workspace, etc) that they do not have permission for.
404	ResourceNotFoundException	The requested resource could not be found. Example - If a given project id, workspace id or a network id does not exist in the database.
500	Internal Server Error (ParseErrorException, MethodInvocationException, QuadrigaStorageException, JSONException, Exception)	An error has occurred in the server while processing the request. ParseErrorException and MethodInvocationException occur if there is an error creating an xml string from the velocity templates. QuadrigaStorageException occurs when there is an issue accessing the Quadriga database. JSONException occurs while creating a JSON Object that is sent as part of the response.

Quadriga Documentation