Integration with PayPo payment gateway

We have website under Oh!Zuza | Oh!Zuza Vanilla night&day - Strona główna connected to Cloudflare and we have problem with response after successful payment. Shop is based on woocommerce. After payment order doesn’t change the status to paid. There is no response to the store from the payment gateway.

We tested on a backup of the store only without Cloudflare and the answer about the correct payment came right away.

It is possible that something is blocking in the firewall. We tried to add rules on IP, but it didn’t help. What else can we check?