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=5720541518&hash=689be10ca1bf2f662236b0d894db26ab&redirect_to=https%3A%2F%2Fu.limo%2Ftag%2F%25E7%25AE%2580%25E7%25BA%25A6%2F' caused an error:

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