Jetpack error after update (and related post never showing)

Hi:

I installed Jetpack in my test site http://web2014.cincuentamas.com/ to use Related Post feature. First it got stuck in “Indexing request queued and waiting…”. Now, after the update, I get this error:

(
    [headers] => Array
        (
            [server] => nginx
            [date] => Thu, 30 Oct 2014 15:44:57 GMT
            [content-type] => text/plain;charset=utf-8
            [connection] => close
            [x-pingback] => https://jetpack.wordpress.com/xmlrpc.php
            [expires] => Wed, 11 Jan 1984 05:00:00 GMT
            [cache-control] => no-cache, must-revalidate, max-age=60
            [pragma] => no-cache
            [x-hacker] => Jetpack Test
        )

    [body] => {"error":"Unknown Error","error_description":"An unknown error has occurred."}
    [response] => Array
        (
            [code] => 400
            [message] => Bad Request
        )

    [cookies] => Array
        (
        )

    [filename] =>
)

Any help will be very welcome. Thanks!

https://wordpress.org/plugins/jetpack/