error handling when service is on down or in maintenance

acme.js

@@ -92,6 +92,9 @@ ACME.create = function create(me) {
 		}
 		return p.then(function() {
 			return ACME._directory(me).then(function(resp) {
+				if (resp.type && resp.type.indexOf("error") >= 0) {
+					throw new Error(resp.detail);
+				}
 				return fin(resp.body);
 			});
 		});