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=6862822851&hash=f154ae0d339d4354998b55ffa095db2e&redirect_to=https%3A%2F%2Fu.limo%2Ftag%2F%25E7%2589%25B9%25E6%2595%2588%25E9%25A2%2584%25E8%25AE%25BE%2F' caused an error:

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