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=bf59a9707a&notice_str=3137705559&hash=398f4d199f1a16da81a3be74e05ed57a&redirect_to=https%3A%2F%2Fu.limo%2F12240%2F' caused an error:

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