Hello everyone, **I created a certificat using openssl using the steps below ** Generate a Certificate Signing Request (ecccertreq.csr) Generate key pair in a key file Code openssl ecparam -genkey -name prime256v1 -out ecckey.key Generate CSR from key pair in key file Code openssl req -new -sha256 -key ecckey.key -out ecccertreq.csr -subj '/O=Nahdi Merchant Identity' Upload the Payment Processing Certificate CSR Download the Apple signed Payment Processing Certificate The certificate file (apple_pay.cer) appears in my Downloads folder Generate the .p12 file (ecckeystore.p12) Convert apple_pay.cer to PEM Code openssl x509 -inform DER -in apple_pay.cer -out apple_pay.pem Import merchant certificate and private key to generate .p12 Code openssl pkcs12 -export -out ecckeystore.p12 -inkey ecckey.key -in apple_pay.pem But I am getting this error when testing using the curl_test.php file and also when trying to make a payment on our website, we already have a working certificat for another merchant id and we don't get the same error Verbose info: cURL Error 56 - OpenSSL SSL_read: error:14094418:SSL routines:ssl3_read_bytes:tlsv1 alert unknown ca, errno 0 Verbose information * Trying 17.141.128.71:443... * TCP_NODELAY set * Connected to apple-pay-gateway.apple.com (17.141.128.71) port 443 (#0) * ALPN, offering h2 * ALPN, offering http/1.1 * successfully set certificate verify locations: * CAfile: /etc/ssl/certs/ca-certificates.crt CApath: /etc/ssl/certs * SSL connection using TLSv1.3 / TLS_AES_128_GCM_SHA256 * ALPN, server accepted to use http/1.1 * Server certificate: * subject: businessCategory=Private Organization; jurisdictionC=US; jurisdictionST=California; serialNumber=C0806592; C=US; ST=California; L=Cupertino; O=Apple Inc.; CN=apple-pay-gateway.apple.com * start date: Jul 24 19:05:42 2024 GMT * expire date: Oct 22 19:15:42 2024 GMT * subjectAltName: host "apple-pay-gateway.apple.com" matched cert's "apple-pay-gateway.apple.com" * issuer: C=US; O=Apple Inc.; CN=Apple Public EV Server RSA CA 1 - G1 * SSL certificate verify ok. > POST /paymentservices/paymentSession HTTP/1.1 Host: apple-pay-gateway.apple.com Accept: */* Content-Length: 131 Content-Type: application/x-www-form-urlencoded * upload completely sent off: 131 out of 131 bytes * OpenSSL SSL_read: error:14094418:SSL routines:ssl3_read_bytes:tlsv1 alert unknown ca, errno 0 * Closing connection 0 code-block