Issue with front-end ajax, getting a 302 redirect when accessing wp-admin/admin-ajax.php

Question

I want to use wp ajax for frontend logged in user but showing error of 302 Found and call home page. it is working fine for admin users and non logged in users.

here is network log screenshot:

i have used both ajax function like below:

add_action('wp_ajax_add_sale', 'add_sale');
add_action('wp_ajax_nopriv_add_sale', 'add_sale');

add_sale() below:

<?php
function add_sale() {
    die("hello");
    $salevehicleid = $_POST['salevehicleid'];
    $saleuserhidid = $_POST['saleuserhidid'];
    $saleusername = $_POST['saleusername'];
    $saleuseremail = $_POST['saleuseremail'];

    $saledate = date('Y-m-d H:i:s');

    $letsaleplaced = true;

    $response = array();

    // $saleuserhidid = (int)0;

    // if(is_user_logged_in()){
    //     $user_id = get_current_user_id();
    //     if ($user_id == 0) {
    //         $saleuserhidid = (int)0;
    //     } else {
    //         $saleuserhidid = (int)$user_id;
    //     }
    // }else{
    //     $saleuserhidid = (int)0;
    // }

    // echo $saleuserhidid;

    if($saleuserhidid == (int)0){
        global $wp_query;
        $args = array(
            'post_type'=>'my_custom_sale', 
            'post_status'=>'publish',
            'meta_query' => array(
                'relation' => 'AND',
                array(
                    'key' => 'vehicleid',
                    'value' => $salevehicleid,
                    'compare' => '=='
                ),
                array(
                    'key' => 'usermail',
                    'value' => $saleuseremail,
                    'compare' => '=='
                )
            )
        );
        $wp_query = new WP_Query( $args );

        global $post;

        if ( $wp_query->have_posts() ) :
            $letsaleplaced = false;
        endif;

    }else{
        global $wp_query;
        $args = array(
            'post_type'=>'my_custom_sale', 
            'post_status'=>'publish',
            'meta_query' => array(
                'relation' => 'AND',
                array(
                    'key' => 'vehicleid',
                    'value' => $salevehicleid,
                    'compare' => '=='
                ),
                array(
                    'key' => 'usermail',
                    'value' => $saleuseremail,
                    'compare' => '=='
                ),
                array(
                    'key' => 'userid',
                    'value' => $saleuserhidid,
                    'compare' => '=='
                )
            )
        );
        $wp_query = new WP_Query( $args );

        global $post;

        if ( $wp_query->have_posts() ) :
            $letsaleplaced = false;
        endif;
    }

    if($letsaleplaced){
        $title = "sale";
        $post_type = 'my_custom_sale';

        $new_sale = array(
            'post_title'    => $title,
            'post_status'   => 'publish',          
            'post_type'     => $post_type,
            array(
                'public' => true,
                'capability_type' => $post_type,
                'capabilities' => array(
                    'publish_posts' => 'publish_'.$post_type,
                    'edit_posts' => 'edit_'.$post_type.'s',
                    'delete_posts' => 'delete_'.$post_type,
                    'edit_post' => 'edit_'.$post_type,
                    'delete_post' => 'delete_'.$post_type,
                    'read_post' => 'read_'.$post_type,
                    'map_meta_cap' => true
                )
            )
        );

        $pid = wp_insert_post($new_sale);

        add_post_meta($pid, 'userid', $saleuserhidid, true);
        add_post_meta($pid, 'usermail', $saleuseremail, true);
        add_post_meta($pid, 'username', $saleusername, true);
        add_post_meta($pid, 'vehicleid', $salevehicleid, true);
        add_post_meta($pid, 'saledate', $saledate, true);

        //--owner mailing--//
        $owneremailid = "";
        $didsubject = "New Buy Request Added";

        $finalname = "";

        $vehicledata = get_post_meta( $salevehicleid );
        if(!empty($vehicledata)){
            $usersdata = get_user_by( 'id', $vehicledata['customer'][0]);
            $owneremailid = $usersdata->data->user_email;

            $usernamedata = get_userdata($vehicledata['customer'][0]);
            if(!empty($usernamedata)){
                if($usernamedata->first_name != '' && $usernamedata->last_name != ''){
                    $finalname = $usernamedata->first_name." ".$usernamedata->last_name;
                }else{
                    $finalname = $usersdata->data->user_login;
                }
            }else{
                $finalname = $usersdata->data->user_login;
            }
        }
        $carlink = home_url().'/view-vehicle/'.$salevehicleid;
        $content = "<div style='text-align:left;'>Hi, ".ucwords($saleusername)." is interested in buying your <a href='".$carlink."'>vehicle</a>.</div><br> 
            <div style='text-align:left;'>Please contact : Using this email address ".$saleuseremail." to arrange a viewing.</div>";

        $header = "Content-Type: text/html; charset=ISO-8859-1\r\n";
        if(!empty($owneremailid)){
            wp_mail($owneremailid, $didsubject, $content, $header);
        }


        $adminemailid = get_bloginfo('admin_email');
        $didsubject = "New Buy Request Added";

        $carlink = home_url().'/view-vehicle/'.$salevehicleid;
        $admincontent = "<div style='text-align:left;'>".ucwords($saleusername)." place a buy request to ".ucwords($finalname)." <a href='".$carlink."'>vehicle</a> and email address is ".$saleuseremail."</div>";

        $header = "Content-Type: text/html; charset=ISO-8859-1\r\n";
        if(!empty($adminemailid)){
            wp_mail($adminemailid, $didsubject, $admincontent, $header);
        }

        //--admin mailing--//

        $response['status'] = true;
        $response['bidid'] = $pid;
        $response['message'] = 'Buy request added successfully';
    }else{
        $response['status'] = false;
        $response['bidid'] = 0;
        $response['message'] = 'This user can not send buy request.';
    }

    echo json_encode($response);
    die();
}

Answer 1

Below function works for me by adding !defined('DOING_AJAX') in condition.

function custom_blockusers_init() {
  if ( is_admin() && !defined('DOING_AJAX') && ( 
  current_user_can('usercrp') || current_user_can('userpcp') ||  
  current_user_can('subscriber') || current_user_can('contributor') || 
  current_user_can('editor'))) {
    session_destroy();
    wp_logout();
    wp_redirect( home_url() );
   exit;
  }
 }
add_action( 'init', 'custom_blockusers_init' );