Not Able to Submit App

Hello, I submitted the app to Facebook for review, but it wasn’t approved. Here’s what they told:

Feedback From Your Last Submission (Yesterday at 8:04 PM)

Your bot did not respond when we messaged your page

We did not receive an automated response when we messaged your Page. Bots should respond to all input from the user within 30 seconds so that the experience feels like a continuous conversation. Please ensure that your experience is functional before you resubmit. Please visit our App Review Rejections Results Guide to learn more.
You may find helpful to check out our Example Messenger Bots. Our Developer Community Forum is also a great resource to find related content or post new questions. Thank you.

Here’s another message have:

Your Webhooks subscription for callback URL https://lemouniq.com/wp-admin/admin-ajax.php?action=wacv_fb_message has not been accepting updates for at least 10 minutes. Please verify that your callback server is functioning. Visit our reference documentation to learn how to update your callback URL.

Click here to see more details about the recent Messenger webhook errors.

If your callback URL is still failing after 50 minutes your subscription will be disabled. To reactivate, just make a POST request with the same parameters or visit the Webhooks tab in the app dashboard.