Great 🙂
Please ensure you have made a complete backup in the first instance and then open up the-events-calendar/lib/the-events-calendar.class.php then find line 4340 which should look like:
echo json_encode( $response );
Try changing this to:
echo json_encode( utf8_encode($response) );
If it doesn’t help / causes problems for any reason please simply restore it to how it was before making the edit. Does that help at all with this situation?