AJAX Front-end User Registration Form not displaying macro errorList
No errors are displayed because you are using AJAX to post your data. The errorList function works only with "regular" POST flow. When ajax response is available you need to grab it and append errors yourself.

Try this code:

$('#registrationForm').submit(function(ev) {
    ev.preventDefault();

    var data = $(this).serialize();

    $.post('/', data, function(response) {

        if (response.success) {
            console.log("success")
        } else {
            console.log(response.errors);
            appendErrors(response.errors);
        }

    });
});

function appendErrors(errors) {
    $.each(errors, function(field, errors) {
        appendError(field, errors);
    });
}

function appendError(field, errors) {
    var $errorList = $('&lt;ul&gt;');

    $.each(errors, function(index, error) {
        $errorList.append($('&lt;li&gt;').html(error));
    });

    $("input[name=" + field + "]").after($errorList);
}