Hi,
Please check if the message appears marked as “paid” in the messages list.
If it appears marked as paid then the problem is in the WordPress emai delivery settings. Please check if your hosting service requires some specific configuration to send emails from PHP/WordPress websites. The plugin uses the settings specified into the WordPress website to deliver the emails, if your hosting has some specific requirements like a fixed “from” address or a custom “SMTP” server those settings must be configured into the WordPress website.
On the other hand if the item doesn’t appear marked as “paid” in the messages list then the problem is the PayPal IPN notification not reaching the website, in that case please check if the seller PayPal account has the IPN notifications enabled.
Thank you for using the plugin!