PayPal: no email notification after payment

Hello to all,
in an old ecommerce, I have updated WordPress and installed plugins including WooCommerce.

After the update I realized that if a user chooses any type of payment other than PayPal, the purchase process ends well with sending the email to the buyer and the seller.

In case you choose PayPal instead:
1) the user is directed to the PayPal page
2) make the payment
3) the payment screen appears successful
after which, through a special button, the user returns to the seller’s site where a summary screen is displayed but:
– no email is sent between the seller and the buyer
– the status of the order remains “Pending …”

Why?
What could have changed compared to before?

Thank you.