highcharts graph no show yaxis values - highcharts

Question

The graph does not show the y-axis values​​. Could anyone help me with this? thanks.
If I put the value of prueba in the series data, everything worsk correctly
the prueba array and the dinero array are displayed correctly.
Thanks,
$.getJSON('http://localhost/jquery/grafica4.php', function(data) {
var dinero = [];
var categories = [];
var prueba = [79, 71, 66,44,42,38,32,10];
$.each(data, function(index, value) {
categories.push(data[index].producto_id);
dinero.push(data[index].cantidad);
alert("hola");
});
alert(dinero);
alert(prueba);
chart4 = new Highcharts.Chart({
chart: {
renderTo: 'container3',
type: 'column'
},
title: {
text: 'Productos más vendidos'
},
xAxis: {
categories: categories
},
yAxis: {
min: 0,
title:
text: 'Cantidad'
},
labels: {
formatter: function() {
return this.value; // clean, unformatted
}
}
},
legend: {
layout: 'vertical',
backgroundColor: '#FFFFFF',
align: 'left',
verticalAlign: 'top',
x: 100,
y: 70,
floating: true,
shadow: true
},
tooltip: {
formatter: function() {
return ''+
'<b>'+'Producto:'+this.x +'</b>'+'<br/>'+ this.y+ ' unidades';
}
},
plotOptions: {
column: {
pointPadding: 0.3,
borderWidth: 0
}
},
series: [{
name: 'Cantidad',
data: dinero
}],
exporting: {
filename: 'Facturacion-de-empleados'
}
});
});