I have uninstalled a previous version of virtualbox using sudo apt-get remove virtualbox and tried to install the latest version using the information from this page.
I did
wget -q https://www.virtualbox.org/download/oracle_vbox.asc -O- | sudo apt-key add -
and
sudo apt-get update
my /etc/apt/sources.list file contains:
deb http://download.virtualbox.org/virtualbox/debian trusty contrib
and the error I get after update is:
Err http://download.virtualbox.org trusty InRelease
Err http://download.virtualbox.org trusty Release.gpg
Unable to connect to download.virtualbox.org:http: [IP: 62.253.3.177 80]
Fetched 4,124 kB in 4min 0s (17.2 kB/s)
Reading package lists... Done
W: Failed to fetch http://download.virtualbox.org/virtualbox/debian/dists/trusty/InRelease
W: Failed to fetch http://download.virtualbox.org/virtualbox/debian/dists/trusty/Release.gpg Unable to connect to download.virtualbox.org:http: [IP: 62.253.3.177 80]
W: Some index files failed to download. They have been ignored, or old ones used instead.