Fail to get reviews through rest api

Hello

I plan to use gd and its rest api to build an mobile app. http://ec2-107-23-254-134.compute-1.amazonaws.com, is a wordpress environment for test.
WordPress Version: 4.6
Current WordPress Theme: Twenty Sixteen version 1.3
PHP Version: 7.0.8
MySQL Version: 5.7.13

Once I send a get request to http://ec2-107-23-254-134.compute-1.amazonaws.com/wp-json/geodir/v1/reviews. I get following error

<br />

<b>Fatal error</b>: Uncaught Error: Call to undefined function geodir_reviewrating_comments_shorting() in /opt/bitnami/apps/wordpress/htdocs/wp-content/plugins/geodir_api-master/includes/geodir-rest-functions.php:600
Stack trace:

#0 /opt/bitnami/apps/wordpress/htdocs/wp-includes/plugin.php(291): geodir_rest_comments_clauses(Array, Object(WP_Comment_Query))

#1 /opt/bitnami/apps/wordpress/htdocs/wp-includes/class-wp-comment-query.php(863): apply_filters_ref_array(‘comments_clause…’, Array)

#2 /opt/bitnami/apps/wordpress/htdocs/wp-includes/class-wp-comment-query.php(405): WP_Comment_Query->get_comment_ids()

#3 /opt/bitnami/apps/wordpress/htdocs/wp-includes/class-wp-comment-query.php(357): WP_Comment_Query->get_comments()

#4 /opt/bitnami/apps/wordpress/htdocs/wp-content/plugins/geodir_api-master/includes/class-geodir-rest-reviews-controller.php(173): WP_Comment_Query->query(Array)

#5 /opt/bitnami/apps/wordpress/htdocs/wp-includes/rest-api/class-wp-rest-server.php(907): Geodir_REST_Reviews_Controller->get_items(Object(WP_REST_Reque in

<b>/opt/bitnami/apps/wordpress/htdocs/wp-content/plugins/geodir_api-master/includes/geodir-rest-functions.php</b> on line <b>600</b><br />

Did I do somthing wrong?

Thank you very much!

Qixuan