List of errors when trying to run sudo apt-get update:
Err http://mirrordirector.raspbian.org jessie/contrib armhf Packages
404 Not Found [IP: 93.93.128.193 80]
Ign http://mirrordirector.raspbian.org jessie/contrib...
W: Failed to fetch http://mirrordirector.raspbian.org/raspbian/dists/jessie/contrib/binary-armhf/Packages 404 Not Found [IP: 93.93.128.193 80]
E: Some index files failed to download. They have been ignored, or old ones used instead.
Solution:
https://forums.raspberrypi.com/viewtopic.php?t=318358
Source:
https://www.raspberrypi.com/software/operating-systems/