If the result of your HTTP POST is twofold: 1) A normal HTTP response that has the success/failure and data returned as a result and separately 2) the server does an HTTP post to a 2nd URL. You'll need to handle #1 as you are now, by connecting the QNetworkAccessManager::finished signal to a slot, but for #2, you'll essentially have to write a little web server that listens on 127.0.0.1 and port 5000, etc.

What still doesn't make sense to me is that 127.0.0.1 is a special address for the localhost and is not a routeable IP address... There should be no way for a server external to your local host that can connect to 127.0.0.1:5000, so something isn't quite making sense... If you had said that the server does an HTTP POST to your public IP address on a specific port, that would make sense to me, but it doesn't because you're saying it's a POST to 127.0.0.1.

Sorry I can't be of more help!