can not connect to jetpack

hello,

i can not connect to jetpack from my wordpress site.

this are the debug info:

Your site isn’t reaching the Jetpack servers.

HTTP:
Resolving timed out after 5647 milliseconds

It looks like your site can not communicate properly with Jetpack.

SELF:
Array
(
[headers] => Array
(
[server] => nginx
[date] => Sun, 11 Oct 2015 10:04:24 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
[x-ac] => 3.fra _sat
)

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

[cookies] => Array
(
)

[filename] =>
)

can any help me?
Thanky

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