google cloud platform – Unable to receive XMPP upstream messages

App Server is connected to XMPP and can send messages to the client in one go. But the client sends upstream messages through FirebaseMessaging.getInstance().send(remotemsage), and the App Server cannot receive it.

upstream message：

FirebaseMessaging.getInstance().send(new RemoteMessage.Builder(to)
.setMessageId(messageId)
.addData(“message”, “111”)
.build());
@Override
public void onMessageSent(@NonNull String msgId) {
super.onMessageSent(msgId);
Log.e(“TAG”, “onMessageSent: ” + msgId);
}
onMessageSent() Log will print.

try: `First, the App Server is running on a personal computer and cannot receive it; Secondly, the App Server is run on the Singapore server, the client device is connected to the VPN, and the uplink is sent, but it still cannot be received;

What should I do to let the App server receive the upstream message?`