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=8addc78709&notice_str=8136154322&hash=203b5f59781405fe0d20183180f3dc9d&redirect_to=https%3A%2F%2Fu.limo%2Ftag%2F%25E5%2585%25B6%25E4%25BB%2596logo%2F' caused an error:

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