Update Xcode not working "Could not connect to the server"

Hi,

I installed El Capitan a few days ago.

Now I'm trying to update Xcode, but it does not work, Appstore tells me "Could not connect to the server".

In the log, i see the following message :

09/10/15 19:15:33,753 storedownloadd[466]: tcp_connection_destination_perform_socket_connect 30 connectx to 2.18.244.115:80@0 failed: [64] Host is down

09/10/15 19:15:33,754 storedownloadd[466]: tcp_connection_destination_perform_socket_connect 30 connectx to 2.18.244.96:80@0 failed: [64] Host is down

I was able to update Keynote, The Unarchiver, and a brother printer driver, but Xcode fails.

Would you know why and how to fix that ?