Not connecting Landscape client

Good morning,

I am trying to activate the LandScape client on my network that is behing a proxy server. I can connect to landscape.canonical.com through 80 and 443 ports, but not activating the client

When I try to activate it I get:

*****@**2SUB01:/etc/landscape$ sudo landscape-config
[sudo] password for *****:

This script will interactively set up the Landscape client. It will
ask you a few questions about this computer and your Landscape
account, and will submit that information to the Landscape server.
After this computer is registered it will need to be approved by an
account administrator on the pending computers page.

Please see https://landscape.canonical.com for more information.

The computer title you provide will be used to represent this
computer in the Landscape user interface. It's important to use
a title that will allow the system to be easily recognized when
it appears on the pending computers page.

This computer's title [**2SUB01]:

You must now specify the name of the Landscape account you
want to register this computer with. You can verify the
names of the accounts you manage on your dashboard at
https://landscape.canonical.com/dashboard

Account name [******]:

A registration password may be associated with your Landscape
account to prevent unauthorized registration attempts. This
is not your personal login password. It is optional, and unless
explicitly set on the server, it may be skipped here.

If you don't remember the registration password you can find it
at https://landscape.canonical.com/account/*****

Account registration password:
Please confirm:

Passwords must match.

Account registration password:
Please confirm:

The Landscape client communicates with the server over HTTP and
HTTPS. If your network requires you to use a proxy to access HTTP
and/or HTTPS web sites, please provide the address of these
proxies now. If you don't use a proxy, leave these fields empty.

HTTP proxy URL [http://**.**.**.*:****/]:
HTTPS proxy URL [http://**.**.**.*:****/]:

Landscape has a feature which enables administrators to run
arbitrary scripts on machines under their control. By default this
feature is disabled in the client, disallowing any arbitrary script
execution. If enabled, the set of users that scripts may run as is
also configurable.

Enable script execution? [Y/n]

By default, scripts are restricted to the 'landscape' and
'nobody' users. Please enter a comma-delimited list of users
that scripts will be restricted to. To allow scripts to be run
by any user, enter "ALL".

Script users [ALL]:

You may provide tags for this computer e.g. server,hardy.

Tags [Server]:
 * Stopping landscape-client daemon [ OK ]
 * Starting the landscape-client daemon [ OK ]

Request a new registration for this computer now? (Y/n): Y
Please wait... We were unable to contact the server. Your internet connection may be down. The landscape client will continue to try and contact the server periodically.

My client.conf:

*****@**2SUB01:/etc/landscape$ sudo cat /etc/landscape/client.conf
[client]
url = https://landscape.canonical.com/message-system
ping_url = http://landscape.canonical.com/ping
data_path = /var/lib/landscape/client
http_proxy = http://********/
tags = Server
computer_title = **2SUB01
account_name = ****
registration_password = *******
include_manager_plugins = ScriptExecution
script_users = ALL
https_proxy = http://******/

I can access through https and http to canonical from the terminal,

Thanks a lot,

regards,