Error: 404 Not Found

Sorry, the requested URL 'http://u.limo/wp-admin/admin-ajax.php?channel_id=social_wechat&action=xh_social_channel&tab=login_redirect_to_authorization_uri&xh_social_channel=eb763ed831&notice_str=9185514473&hash=25211cd569e2e71da958698e29e2f4ae&redirect_to=https%3A%2F%2Fu.limo%2F12211%2F' caused an error:

Not found: '/wp-admin/admin-ajax.php'