Admin section showing CUSTOM Permalink structure thus resulting in permission error [closed]

I solved this issue by doing as shown below.

I used Woo commerce Gift registry plugin replace the code with the below code in magenest-giftregistry-admin.php

<?php
if ( ! defined( 'ABSPATH' ) ) exit; // Exit if accessed directly
if (! defined ( 'ABSPATH' ))
    exit (); // Exit if accessed directly
class Magenest_Giftregistry_Admin {
        /**
         * Constructor.
         */
    public function __construct() {

    }
    public function giftregistry_manage() {
        if (isset ( $_REQUEST ['delete'] )) {
            if (isset ( $_REQUEST ['id'] ))
                $this->delete ( $_REQUEST ['id'] );
        } elseif (isset ( $_REQUEST ['edit'] )) {
            if (isset ( $_REQUEST ['id'] ))
                $this->edit ( $_REQUEST ['id'] );
        } elseif (isset ( $_REQUEST ['delete'] )) {
        } else {
            $this->index ();
        }
    }
    public function giftregistry_manages() {
        $rows_per_page = 10;
        $current = (intval(get_query_var('paged'))) ? intval(get_query_var('paged')) : 1;

        //$rows = $wpdb->get_results('SELECT * FROM subscriber ORDER BY sub_lname ASC');

        $rows = Magenest_Giftregistry_Model::get_all_giftregistry();
        $start = ($current - 1) * $rows_per_page;
        $end = $start + $rows_per_page;
        $end = (sizeof($rows) < $end) ? sizeof($rows) : $end;

        $pagination_args = array(
                'base' => esc_url_raw(@add_query_arg('paged','%#%')),
                'format' => '?page=%#%',
                'total' => ceil(sizeof($rows)/$rows_per_page) + 1,
                'current' => $current,
                'show_all' => False,
                'prev_next'    => True,
                'prev_text'    => __(' Previous'),
                'next_text'    => __('Next '),
                'type' => 'plain',
                'add_args'     => False
        );

        echo paginate_links($pagination_args);
    }

    public static function index() {
        // Test the use of paginate_links

        $rows_per_page = 5;

        $current = (isset($_REQUEST['paged'])&&intval($_REQUEST['paged']) ) ? intval($_REQUEST['paged']) : 1;

        // $rows is the array that we are going to paginate.
        $rows = Magenest_Giftregistry_Model::get_all_giftregistry();

        $max_page = ceil(sizeof($rows)/$rows_per_page);

        global $wp_rewrite,$wp_query;

        $pagination_args = array(
                'base' => esc_url_raw(@add_query_arg('paged','%#%')),
                'format' => '',
                'total' => ceil(sizeof($rows)/$rows_per_page),
                'current' => $current,
                'show_all' => false,
                'type' => 'plain',
        );

        //if( $wp_rewrite->using_permalinks() )
        //  $pagination_args['base'] = user_trailingslashit( trailingslashit( remove_query_arg('s',get_pagenum_link(1) ) ) . 'page/%#%/', 'paged');

        if( !empty($wp_query->query_vars['s']) )
            $pagination_args['add_args'] = array('s'=>get_query_var('s'));

        echo paginate_links($pagination_args);

        $start = ($current - 1) * $rows_per_page;
        $end = $start + $rows_per_page;
        $end = (sizeof($rows) < $end) ? sizeof($rows) : $end;

        echo '<table id="wishlit-tbl" class="wp-list-table widefat fixed">';
        ?>
<thead>
    <tr>
        <th>
        <?php echo __('User id')?>
        </th>
        <th>
        <?php echo __('Registrant name')?>
        </th>
        <th>
        <?php echo __('Registrant email')?>
        </th>
        <th>
        <?php echo __('Date Time')?>
        </th>
        <th>
        <?php echo __('Delete')?>
        </th>
        <th>
        <?php echo __('Edit')?>
        </th>
    </tr>
</thead>
<?php 

        for ($i=$start;$i < $end ;++$i ) {
            $row = $rows[$i];
            $phpdate = strtotime( $row['event_date_time'] );
            $order_date = date('d M, Y h:i A', $phpdate);
            $http_schema="http://";
            if (isset($_SERVER['HTTPS']) && $_SERVER['HTTPS'])  {
                $http_schema="https://";
            }
            $delete_link = $http_schema. $_SERVER["HTTP_HOST"] . $_SERVER["REQUEST_URI"] . '&delete=1';
            $edit_link = $http_schema. $_SERVER["HTTP_HOST"] . $_SERVER["REQUEST_URI"] . '&edit=1';
            echo '<tr>';
            ?>
<td><?php echo $row['user_id']?> </td>
<td><?php echo $row['registrant_firstname']?> </td>
<td><?php echo $row['registrant_email']?> </td>
<td><?php echo $order_date ?> </td>
<td><a href="https://wordpress.stackexchange.com/questions/203400/<?php echo $delete_link."&id='.$row['id'] ?>"><?php echo __('Delete', GIFTREGISTRY_TEXT_DOMAIN)?></a>
</td>
<td><a href="<?php echo $edit_link.'&id='.$row['id'] ?>"><?php echo __('Edit', GIFTREGISTRY_TEXT_DOMAIN)?></a>
</td>
<td></td>


<?php 
            echo '</tr>';

        }
        echo '</table>';
    }

    public function delete($id) {

        Magenest_Giftregistry_Model::delete_giftregistry($id);
    }
    public function edit($id) {
        ?>
        <br>
        <button onclick="window.location.href="<?php echo get_admin_url(null,"admin.php?page=gift_registry')?>'" name="back" type="button" class="button button-primary button-large" id="back" accesskey="p" value="Back"><?php echo  __('Gift registry manage')?> </button>
        <?php 
        echo '<h2>Gift registry</h2>';
        ob_start();
        $template_path = GIFTREGISTRY_PATH.'template/account/';
        $default_path = GIFTREGISTRY_PATH.'template/account/';

        wc_get_template( 'add-giftregistry.php', array(
        'wid'       =>$id,

        ),$template_path,$default_path
        );
        echo  ob_get_clean();

        /////////////////////////////////////////////////////////////////////
        /////////////////////////////GIFT REGISTRY ITEMS/////////////////////
        ////////////////////////////////////////////////////////////////////
        $items = Magenest_Giftregistry_Model::get_items_in_giftregistry($id);
        ob_start();

        $template_path = GIFTREGISTRY_PATH.'template/account/';
        $default_path = GIFTREGISTRY_PATH.'template/account/';


        wc_get_template( 'my-giftregistry.php', array(
        'items'         =>$items,
        'wid'       =>$id
        ),$template_path,$default_path
        );
        echo  ob_get_clean();
    }

}