We’ve moved our software distribution to packages.chef.io

@aespinosa The following appears to be working as expected on Ubuntu 14.04:

# enable https support in apt
sudo apt-get install apt-transport-https -y

# Ensure Chef's public key is installed (we sign the repo metadata with it)
wget -qO - https://downloads.chef.io/packages-chef-io-public.key | sudo apt-key add -

# add a source for Chef's stable repo
echo "deb https://packages.chef.io/stable-apt trusty main" | sudo tee /etc/apt/sources.list.d/chef-stable.list    

# install apt-cacher-ng
sudo apt-get install apt-cacher-ng -y

# configure the proper pass-through pattern
echo "PassThroughPattern: (packages\.chef\.io):443$" | sudo tee --append /etc/apt-cacher-ng/acng.conf    

# configure the local machine to use apt-cacher-ng for all requests
echo 'Acquire::http { Proxy "http://localhost:3142"; };' | sudo tee /etc/apt/apt.conf.d/00proxy

# start apt-cacher-ng (be sure to restart it anytime a config change is made)
sudo /etc/init.d/apt-cacher-ng restart

# update the cache
sudo apt-get update

Note the sudo /etc/init.d/apt-cacher-ng restart.