How can I fix PPA Failed to fetch errors while running apt-get update on Ubuntu 14.04?

How can I fix the following errors I received during sudo apt-get update on Ubuntu 14.04 so I can upgrade to Ubuntu 16.04?

W: Failed to fetch http://ppa.launchpad.net/ethereum/etherum/ubuntu/dists/unity/main/binary-amd64/Packages  403  Forbidden

W: Failed to fetch http://ppa.launchpad.net/ethereum/etherum/ubuntu/dists/unity/main/binary-i386/Packages  403  Forbidden

I have tried everything I can find on here relating to this issue & don't understand what I may be doing wrong. I am fairly new to Ubuntu / Linux systems so please bear with me & try to help me.

Solution 1:

Try launch "Software & update" utility, and disable these PPA`s on tab "Other"