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=eae32193e9&notice_str=4155138503&hash=ad23a8333d7a95389bd86eaacc6eb183&redirect_to=https%3A%2F%2Fu.limo%2Ftag%2F%25E7%25AB%2596%25E5%25B1%258F%25E8%25A7%2586%25E9%25A2%2591%2F' caused an error:

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