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=bf59a9707a&notice_str=7704650319&hash=52100e096b929320e703a92d5cf8d321&redirect_to=https%3A%2F%2Fu.limo%2Ftag%2F%E7%89%B9%E6%95%88%E9%A2%84%E8%AE%BE%2F' caused an error:

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