PayPal issue

Hi,

I would like to ask you about an issue that I have with my PayPal checkout way at my WooCommerce shop. When a client makes an order, even if the payment via PayPal is completed successfully, the IPN of the order is not sent to the shop (I see HTTP response code 404 and Delivery status Retrying at Instant Payment Notification details) and the client is redirected to a 404 page instead of the return URL that I have set at website payment preferences of PayPal: https://www.2thelittlestore.com/checkout/order-received/. I have set up everything correctly according to this article https://docs.woocommerce.com/document/paypal-standard/ and I have also installed SSL on site. Notification URL is https://www.2thelittlestore.com/?wc-api=WC_Gateway_Paypal
Message and delivery is also enabled.

Waiting for your advice on the above issue.

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