datatable not showing all the entries?

In total, I have 11 records, but the table is showing only 10 entries. It also displays "Showing 1 to 10 of 10 entries", but there are 11 entries.
The "next button" also does not work. what is wrong here? Please help
Here is my code:
<script type="text/javascript">
$(document).ready(function() {
var oTable = $('#search_table').dataTable( {
"sDom": 'T<"clear">lrtip',
"bProcessing": true,
//"bServerSide": true,
"sAjaxSource": "{% url 'search_list_json' %}",
"aaSorting": [ [2,'asc'], [1,'desc'] ],
// Disable sorting for the Actions column.
"aoColumnDefs": [ { "bSortable": false, "aTargets": [ 0,4 ] } ],
"iDisplayLength":50
} );
} );
</script>
JSON object: (I have reduced aaData for simplicity)
{ "iTotalRecords": 11, "aaData": [[ .....], [....]], "sEcho": 0, "iTotalDisplayRecords": 11}