The fix

See code below

The story

I recently upgraded to 17.10 after I started to get 404 errors when trying to install packages. Yeah, I should upgrade more often, but something always breaks when you upgrade.

This time, it was my webserver.

All the packages were installed, but turns out, the Apache php7.1 module needed to be enabled.

sudo a2enmod php7.1

sudo systemctl restart apache2