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=3836001591&hash=a6b47d8b2621fea455f9f2c90f1d6681&redirect_to=https%3A%2F%2Fu.limo%2Ftag%2F%25E7%25AE%2580%25E7%25BA%25A6%25E7%2594%25B5%25E5%25BD%25B1%25E8%25A7%2586%25E5%25B7%25AE%2F' caused an error:

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