Urgent – My website not accepting the reviews with images.

My website https://peekeeper.com/ has Photo Review plugin.
https://peekeeper.com/shop/peekeeper/

When I try to upload image, it’s tsking me/user to https://peekeeper.com/wp-comments-post.php
And showing 404 page not found.

Please review and fix. Please check for both loggedin user and without login user

I have already taken the latest database backup to make sure we do not miss any previous reviews in any case. Please troubleshoot and fix the issue asap. Thank you.