GetHTTPResult.cs

public Text resultText;

private IEnumerator GetResult(string token)
{
    var postData = new List<IMultipartFormSection>();
    postData.Add(new MultipartFormDataSection("Token", token));

    var www = UnityWebRequest.Post("http://192.168.50.150/login.php", postData);
    yield return www.SendWebRequest();

    if (www.result != UnityWebRequest.Result.Success)
    {
        resultText.text = www.error;
    }
    else
    {
        resultText.text = www.downloadHandler.text;
    }
}