Has anyone else received an error "HTTPSConnectionPool" when trying to place a test order in Sandbox?

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/