使用POST方法打开新窗口导致404错误（找不到文件）

I'm currently developing a web based app and encountering a weird problem. When I'm opening new window using POST parameter, it returns 404 error. But when I remove the POST parameter, the page loads fine. The problem happens only when I run the app in production server while when in localhost the problem does not occurs.

Here is an example of the code using POST:

let mapForm = document.createElement("form");
mapForm.target = "Report";
mapForm.method = "POST";
mapForm.action = 'http://1.1.1.1/example.php?sid=123';
let mapInput1 = document.createElement("input");
mapInput1.type = "text";
mapInput1.name = "TES";
mapInput1.value = 'TES VALUE';
mapForm.appendChild(mapInput1);
document.body.appendChild(mapForm);
var newwindow = window.open('',"Report","");
if(newwindow){
mapForm.submit();
}
document.body.removeChild(mapForm);

The above code will result in 404 error in production. Is there something missing in the code that I need to add or maybe permission problem on the server?

SOLVED

my form action is directing to "Report" subfolder in my aws server. It turns out that changing the directory name from "Report" to other solves the issue. Perhaps there is some kind of blocking in the server.