I actually had the same issue yesterday when I upgrade the OS from 14.04 to 16.04 then after ran the Fog upgrade. Going in MYSQL and changing the password for ‘root@localhost’ and ‘root@127.0.0.1’ I reran the installer and mostly everything worked fine afterwards. I found another issue that the NIC was renamed from “eth0” to “ens32” so I had to change the grub file (https://www.itzgeek.com/how-tos/mini-howtos/change-default-network-name-ens33-to-old-eth0-on-ubuntu-16-04.html) then re-run the installer again. If you get the issue with the host page not loading do this,
sudo gedit /etc/php5/apache2/php.ini
Change
memory_limit = 1900M
post_max_size=1900M
upload_max_filesize=1900M
Save Changes
sudo /etc/init.d/apache2 restart
and
Raise the web interface’s memory limit: FOG Configuration -> FOG Settings -> General Settings -> FOG_MEMORY_LIMIT
It’s done in megs, so 128 = 128M, 256 = 256M etc…
After changing this, a reboot is recommended