Same page is loading when clicking pagination in DataTable PHP - php

Question

When I click page number in DataTable, it is not moving to next page instead it loads the whole page again.
But if I click the DataTable sorting button and again I click the pagination page number, the DataTable is working fine. Can anyone help me to solve this. Thanks in advance.
<?php include 'header.php'; ?>
</style>
<!-- Breadcrumbs -->
<section class="bg-gray-7">
<div class="breadcrumbs-custom box-transform-wrap context-dark">
<div class="container">
<h3 class="breadcrumbs-custom-title">Sailing Schedules</h3>
<div class="breadcrumbs-custom-decor"></div>
</div>
<div class="box-transform" style="background-image: url(images/bg-typography.jpg);"></div>
</div>
<div class="container">
<ul class="breadcrumbs-custom-path">
<li>Home</li>
<li class="active">Sailing Schedule</li>
</ul>
</div>
</section>
<br>
<br>
<div class="container">
<?php
ini_set('display_errors', 1);
error_reporting(E_ALL);
// Include config file
require 'config.php';
$sql = "SELECT * FROM long_sched";
if($result = mysqli_query($con, $sql)){
if(mysqli_num_rows($result) > 0){
echo "<table class='table-custom table-custom-primary' id ='long_schd_table'>";
echo "<thead>";
echo "<tr>";
echo "<th>Service Name</th>";
echo "<th>Description</th>";
echo "</tr>";
echo "</thead>";
echo "<tbody>";
while($row = mysqli_fetch_array($result)){
echo "<tr>";
echo "<td><a href=http://localhost/permatest/". $row['long_filepath'] . " target='_self' download>".$row['long_service']."</a></td>";
echo "<td>" . $row['long_desc'] . "</td>";
echo "</tr>";
}
echo "</tbody>";
echo "</table>";
// Free result set
mysqli_free_result($result);
} else {
echo "<p class='lead'><em>No records were found.</em></p>";
} else {
echo "ERROR: Could not able to execute ".$sql." " . mysqli_error($con);
}
// Close connection
mysqli_close($con);
?>
</div>
</section>
<br>
<br>
<?php include 'off_footer.php'; ?>
<script>
$('#long_schd_table').DataTable({});
</script>
The above code is giving this error but in my console I didn't get any error information.