diff --git a/public/class-partnerexpo-core-public.php b/public/class-partnerexpo-core-public.php
index ac66912..d88ad3a 100644
--- a/public/class-partnerexpo-core-public.php
+++ b/public/class-partnerexpo-core-public.php
@@ -56,7 +56,7 @@ class Partnerexpo_Core_Public {
 	public function register_endpoint() {
 		register_rest_route('pexpo/v1', '/query', [
 			'methods'             => 'GET',
-			'callback'            => 'query_partners',
+			'callback'            => [ $this, 'query_partners' ],
 			'permission_callback' => '__return_true',
 		]);
 	}