Launch React Application using post request from another website

Question

I have a simple HTML form:

<form method="post" action="http://localhost:3000">
    <input value="val" name="nam" />
    <button type="submit">Launch</button>
</form>

Now I have a react application which runs on localhost:3000 as follow:

import React from 'react';
import ReactDOM from 'react-dom';
import App from 'components/App/App';

class IndexClass extends React.Component {
    render() {
        return (
            <BrowserRouter>
                <Switch>
                    <Route path="/" exact component={App}/>
                </Switch>
            </BrowserRouter>
        );
    }
}

ReactDOM.render(<Index/>, document.getElementById('root'));

Now, If I type localhost:3000 in my browser url bar, I can successfully launch the application. But If I try to launch my application from simple html form, I get an error:

Cannot POST\

Screenshot:

https://cdn.pbrd.co/images/I0My0wZ.png

I think this is because of post method. How do I solve it?