PHP - HTTP Status Code 505 – HTTP Version Not Supported” error

$(document).on('ready',function(){

    $('#btn-ingresar').click(function(){

        var url = "datos_login.php";

        $.ajax({

           type: "POST",

           url: url,

           data: $("#formulario").serialize(),

           success: function(data)

           {

             $('#resp').html(data);

           }

       });

    });

});