Laravel 7 redirect away shows redirect url on white page

I am redirecting away from Laravel 7 controller and it shows the redirection url just before it redirects to the url. I am using the following code:

private function createPayment($session_token)
{
    ...

    try {
        $response = Http::timeout(30)->withHeaders($headers)->post($url, $body)->json();

        if ($response['statusCode'] != '0000') {
            $this->redirectError($response['statusCode'], $session_token);
        }

        $url= $response['bkashURL'];

        redirect()->away($url)->send();
    } catch (\Throwable $th) {
        $this->redirectError($response['statusCode'], $session_token);
    }
}

// redirect error method:

private function redirectError($code, $session_token = null)
{
    if ($session_token != null) {
        session()->forget($session_token);
    }

    $message = $this->error($code);

    $url = config('global.api_url_bkash') . 'error/' . $message;

    redirect()->away($url)->send();
}

// error method:

private function error($code)
{
    switch ($code) {
        case '2001':
            return 'Invalid App Key';
            break;

        case '2002':
            return 'Invalid Payment ID';
            break;
            
    .....
}

I getting this :

how can I prevent the page not to show the url.

via Chebli Mohamed