Hello, nothing is cache. Please help

Hi @jekiwijaya

Thank you for using our plugin!

The short answer to your question is: yes it is because you use /index.php?rest_route=/ instead of /wp-json/.

Is there any special reason why you are not using the ‘official’ REST URL prefix? We are checking the url if it starts with the result of the WordPress rest_get_url_prefix() function. This function does implement a filter to change wp-json to something else, so perhaps you could try and have it working by using that filter. I must say I have not tested it for your specific use case.
Either way, your question does have a valid point that we should perhaps not only check for wp-json but maybe also whether the query var rest_route is set. I am putting it on a to-do list ??