Installing adobe-flashplugin on Ubuntu 16.10 for Firefox
Solution 1:
Add this line to /etc/apt/sources.list
:
deb http://archive.canonical.com/ubuntu yakkety partner
and run
sudo apt update
Solution 2:
It seems that you are pulling from an old repository.
Go to Software & Updates>Other software.
Then remove the old repository called:
http://archive.canonical.com/ubuntu maverick partner
Then enable the 'Canonical Partners' repository.
If it doesn't exist, click add and type in:
deb http://archive.canonical.com/ubuntu yakkety partner
Next, run:
sudo apt-get install adobe-flashplugin
Flash Player should now be installed. Restart your browser for changes to take effect.