sudo apt-get update fail on Ubuntu 17.04

In my case:

sed -e 's/archive.ubuntu.com/old-releases.ubuntu.com/g' -i /etc/apt/sources.list 
sed -e 's/security.ubuntu.com/old-releases.ubuntu.com/g' -i /etc/apt/sources.list 

you can solve it by: just replace us.archive.ubuntu.com and security.ubuntu.com in /etc/apt/sources.list with old-releases.ubuntu.com and then you'll be able to finish updating.

refer to source 1 and ubuntu forum

it work for me