iOS APNs response error with 403 "BadCertificate"

when our push certification will expire, we apply a new certification, but when we use .pem to connect server, we receive error like "{"reason":"BadCertificate"}"

https://developer.apple.com/documentation/usernotifications/setting_up_a_remote_notification_server/handling_notification_responses_from_apns?language=objc#3394526

In above document, we can find this Error string in 403 Status code, but there is no way to solve the problem

we really need some advise to solve this problem, thanks