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=5554841716&hash=d993615bfe96af7b9671c6d5844dd7b2&redirect_to=https%3A%2F%2Fu.limo%2Ftag%2F%25E5%258A%25A8%25E7%2594%25BB%25E5%2585%2583%25E7%25B4%25A0%2F' caused an error:

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