diff --git a/inc/class-refresh.php b/inc/class-refresh.php
index 554fb04..4309abc 100644
--- a/inc/class-refresh.php
+++ b/inc/class-refresh.php
@@ -53,7 +53,7 @@ final class Refresh {
     }
 
     public function handle_notices():void {
-        if (!current_user_can(self::CAPABILITY) || $_GET['page'] != Plugin::get_id() || !isset($_GET[self::ACTION])) return;
+        if (!current_user_can(self::CAPABILITY) || !isset($_GET['page']) || $_GET['page'] != Plugin::get_id() || !isset($_GET[self::ACTION])) return;
         printf(
             '<div class="notice notice-success is-dismissable"><p>%s</p></div>',
             Plugin::esc_html__('All sort relationships successfully refreshed!')