Instant Update API should be available for Express Checkout in live / production mode. In sandbox mode everything works well - PayPal requests the URL, and then displays the flat rate shipping options -, but in live / production mode PayPal doesn't request the URL at all, the rest of checkout process works well. I assured that all requirements are met for CallbackURL in live / production mode: The URL for CallbackURL begins with https. In sandbox mode, everything works well unchanged. The rest of checkout process works well in live / production and sandbox mode. SetExpressCheckout API call is responded with a response indicating success, without warnings and a valid, working token. The URL is valid and reachable (from all production PayPal IP addresses). HTTPS is supported by server. CallbackURL doesn't exceed the 1024 single-byte characters limit. CallbackURL contains only valid characters (ASCII only, for being sure). CallbackTimeout is set to maximum allowed value of 6 (seconds). The server responds during the 6 seconds timeout. CallbackVersion is set to 61.0 for full support of all available features. (Should the version of calling API also used for Callback version, btw.?) How can I find out the reason why PayPal in live / production doesn't request the URL? Correlation ID of a an Express Checkout which should use Instant Update API (but does not in live / production mode): 510ce7cd28011 Thank you for your answers in advance. With best regards
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