This is the full error message on our website server we're receiving when I followed the steps at https://developer.apple.com/documentation/apple_pay_on_the_web/apple_pay_js_api/requesting_an_apple_pay_payment_session:
HTTPSConnectionPool(host='apple-pay-gateway-cert.apple.com', port=443): Max retries exceeded with url: /paymentservices/startSession/paymentSession
(Caused by SSLError(SSLError(336445449, u'[SSL] PEM lib (_ssl.c:2693)'),))
And error message on my iPhone is:
"Apple Pay Not Completed.
This website was not able to complete the payment. Please try again."
We are trying with the test card numbers from this page - https://developer.apple.com/apple-pay/sandbox-testing/