Access denied for user root@localhost

I have a live Aegir environment that works great with the newest version, and have a new test aegir environment that I keep trying to create without success.

I used the same install script on both environments, but a few months have passed since installing the live environment. The following error message is shown when installing:

Postfix is now set up with a default configuration.  If you need to make
changes, edit
/etc/postfix/main.cf (and others) as needed.  To view Postfix configuration
values, see postconf(1).

After modifying main.cf, be sure to run '/etc/init.d/postfix reload'.

Running newaliases
Setting up aegir3-provision (3.121) ...
adding aegir user...
Adding user aegir to group www-data

Creating config file /etc/sudoers.d/aegir with new version
Setting up aegir3-hostmaster (3.121) ...
'drush' cache was cleared.                                           [success]
ERROR 1045 (28000): Access denied for user 'root'@'localhost' (using password: NO)
dpkg: error processing package aegir3-hostmaster (--configure):
 subprocess installed post-installation script returned error exit status 1
No apport report written because the error message indicates its a followup error from a previous failure.
                                                                                                          dpkg: dependency problems prevent configuration of aegir3:
 aegir3 depends on aegir3-hostmaster (>= 3.121); however:
  Package aegir3-hostmaster is not configured yet.

dpkg: error processing package aegir3 (--configure):
 dependency problems - leaving unconfigured
Processing triggers for libc-bin (2.23-0ubuntu9) ...
Processing triggers for systemd (229-4ubuntu19) ...
Processing triggers for ureadahead (0.100.0-19) ...
Processing triggers for ufw (0.35-0ubuntu2) ...
Errors were encountered while processing:
 aegir3-hostmaster
 aegir3
E: Sub-process /usr/bin/dpkg returned an error code (1)

The problem is always reproducible directly after installing a fresh Ubuntu 16.04.03 and configuring the FQDN environment when running the following script:

sudo apt-get update
sudo apt-get install nginx -y
sudo apt-get install php-fpm -y
sudo apt-get install php7.0-mysql -y
sudo apt-get install php7.0 -y
sudo apt-get install php7.0-gd -y
sudo apt-get install php7.0-mbstring -y
sudo apt-get install php7.0-curl -y
sudo service php7.0-fpm restart
sudo apt-get install software-properties-common
sudo apt-key adv --recv-keys --keyserver hkp://keyserver.ubuntu.com:80 0xF1656F24C74CD1D8
sudo add-apt-repository 'deb [arch=amd64,i386,ppc64el] http://mirror2.hs-esslingen.de/mariadb/repo/10.1/ubuntu xenial main'
sudo apt-get update
sudo apt-get install mariadb-server -y
sudo mysql_secure_installation
sudo echo "deb http://debian.aegirproject.org stable main" | sudo tee -a /etc/apt/sources.list.d/aegir-stable.list
sudo curl http://debian.aegirproject.org/key.asc | sudo apt-key add -
sudo apt-get update
sudo apt-get install aegir3 -y

The problem is also reproducible with the unstable branch. Any help would be greatly appreciated!