jQuery ajax POST returns 500 Internal Server Error

Question

I am trying to perform this ajax post but for some reasons I am getting 500 internal server error.

<?php
while ($row = $query_row->fetch()) {
    $id_row = $row['id'];
    echo '$.ajax({ 
              url: "post.php", 
              data: { from: from_date, to: to_date, user_id: user_id }, 
              type: "POST", 
              dataType: "json", 
              success: function (data) {';
    $total_return = $query_column->rowCount();
    while ($column = $query_column->fetch()) {
        $id_column = $column['id'];
        echo     '$("#td_content_'.$id_row.'_'.$id_column.'").html(data.value_'.$id_row.'_'.$id_column.');';
    }
    echo     '}
          });';
}
?>

The code above works just fine for $total_return <= 10 (no matter SELECT * FROM table_name WHERE id BETWEEN 1 AND 10 or BETWEEN 101 AND 110). If I increase the $total_return to more than 10, the code starts returning error 500 Internal Server Error.

This is not maxJsonLength problem because I also have another ajax post (outside of the while ($query_row->fetch()) at the end of the page which works fine with $total_return = 104.

Solution: I found the solution of my question here: https://talk.plesk.com/threads/mod_security-error-response-body-too-large.350523/

To fix the issue, try to add the following lines in Domains > domain.com > Apache & nginx Settings > Additional directives for HTTP:

<IfModule mod_security2.c>
    SecResponseBodyLimit 546870912
</IfModule>