Error messages

The following error messages can be returned into the response of an operation request.

Message	Description
`invalid request`	The request could not be processed on the server side, maybe because it had an invalid format.
`invalid key`	The provided API key was incorrect.
`unauthorized`	The user was not authorized to perform the requested operation.
`insufficient credits`	The user does not have enough credits to start the requested scan.
`invalid operation`	The requested operation was invalid.
`invalid tool_id`	The specified `tool_id` was invalid.
`invalid tool_params`	The specified parameters were invalid for the tool.
`invalid target`	The target cannot be scanned due to lack of authorization.
`invalid workspace`	The requested workspace does not exist.
`invalid scan_id`	The specified `scan_id` was invalid.
`invalid format`	The requested output format is invalid.
`internal error`	An internal error has occurred.