Full Calendar - Error Loading JSON events - php

Question

I am having trouble with Full Calendar (FC) to read the JSON object I have returned from my database to display events on the calendar. Where could I be overlooking?
My jQuery for FC is here:
$('#calendar').fullCalendar({
defaultView: 'month',
titleFormat: "MMMM YYYY",
header: {
left: 'month,agendaWeek,agendaDay',
center: 'title',
right: 'prevYear,prev,next,nextYear'
},
events: {
url: "../ajax/tutor/json_events.php",
type: "POST",
color: "yellow",
textColor: "black",
error: function() {
alert('There was an error while fetching events.');
}
}
});
The json_events.php is here:
$returnArray = array();
$userID = filter_input(INPUT_GET, "id");
$connect = db();
$stmt = $connect->prepare("SELECT * FROM Lessons WHERE TutorID = 1");
if($stmt->execute()){
$results = $stmt->get_result();
while($row = $results->fetch_assoc()){
$rowArray['start'] = $row['Start'];
$rowArray['end'] = $row['End'];
$rowArray['title'] = $row['CourseTaught'];
array_push($returnArray, $rowArray);
}
$json = json_encode($returnArray);
}
echo print_r($json);
$stmt->close();
The JSON object displays perfectly, however the alert is being thrown from jquery events for some reason, I am just overlooking the error somehow. A fresh pair of eyes would be useful.

Answer 1

Add square brackets around $json, something like echo('['.$json.']');

Answer 2

You are returning a human-readable dump of the variable in PHP by using print_r(). Your JavaScript is expecting the true JSON object without formatting.
Simply echo $json; instead of echo print_r($json); and you will get your json object without the surrounding <pre> tags.