diff --git a/notification/method/webpush.php b/notification/method/webpush.php
index a76b7c3..b289612 100644
--- a/notification/method/webpush.php
+++ b/notification/method/webpush.php
@@ -98,9 +98,9 @@ public function get_type(): string
 	*/
 	public function is_available(type_interface $notification_type = null): bool
 	{
-		return $this->config['wpn_webpush_enable']
-			&& $this->config['wpn_webpush_vapid_public']
-			&& $this->config['wpn_webpush_vapid_private'];
+		return $this->config->offsetGet('wpn_webpush_enable')
+			&& $this->config->offsetGet('wpn_webpush_vapid_public')
+			&& $this->config->offsetGet('wpn_webpush_vapid_private');
 	}
 
 	/**