When using the new Sandbox API url we constantly get HTTP error code 500 with the following body:

{"status": 500, "error": {"type": ["api_error"], "message": "The server encountered an internal error and was unable to complete your request. Either the server is overloaded or there is an error in the application."}}

The URL we use:

Body:

{"query": {"query": {"match_all": {}}}, "titlecase": true, "size": 100}