That’s not using the onChangeRequest revision I shared with you a little bit ago. If you already set the username & password in Settings then there’s no need for you to enter them again in onChangeRequest. From that screenshot you shared with me showed that you had added Username & Password Settings. So I just made a revision to use those new settings you created.
If you don’t want to use plugin Settings then just hardcode the URL like this:
function onChangeRequest(device, attribute, value) {
http.post("http://admin:XXXXXX@192.168.1.222/api/scenes/" + device.Id + "/execute", {});
}