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=68232355da&notice_str=7361861252&hash=f493cb64726e3b03b996d00e477af187&redirect_to=https%3A%2F%2Fu.limo%2Ftag%2F%25E7%25A7%2591%25E6%258A%2580%2F' caused an error:

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