Additional certificate problem of Apple Pay E-Commerce

Dear Apple team and developers,

We integrated Apple Pay E-Commerce on our system and made successful transaction at January using following certificates.

1. Merchant Identity Certificate (generated from our Apple developer account)

2. Payment Processing Certificate (generated from our Apple developer account)

3. Payment Session Server Certificate (used following command and generated from apple-pay-gateway-cert.apple.com:443 test URL)

Command: openssl s_client -connect apple-pay-gateway-cert.apple.com:443 -key MIC_priv.key -cert MIC_merchant_id.pem -showcerts | openssl x509 -outform DER > apay_ident_trusted_cert_test.der

1. Root CA G3 (Downloaded “Apple Root CA – G3 Root” from https://www.apple.com/certificateauthority/ )

But at this month, we got new certificate problem (please check following) when we try to execute Apple Pay E-Commerce transaction. Certificate 'C=US,O=Apple Inc.,OU=Apple Certification Authority,CN=Apple Application Integration CA - G3' is not valid Certificate.

What is this certificate? And Where can I download or generate this certificate from? Could you please advise/give us good information for this certificate problem?

Best Regards, Bilguun Enkhbaatar