Unable to use vagrant ssh on a custom box - ssh

Question

I have successfully created a custom Vagrant box, based on the official ubuntu/xenial64 Vagrant box, but I get this message when I attempt to use vagrant ssh:
==> default: The machine you're attempting to SSH into is configured to use
==> default: password-based authentication. Vagrant can't script entering the
==> default: password for you. If you're prompted for a password, please enter
==> default: the same password you have configured in the Vagrantfile.
The only change to the box is to provision it with NginX. I then use...
vagrant package --vagrantfile <path_to_vagrantfile> --output nginx.box
... where <path_to_vagrantfile> is, in my case, /home/blackslate/.vagrant.d/boxes/ubuntu-VAGRANTSLASH-xenial64/20170822.0.0/virtualbox/Vagrantfile. I follow this with:
vagrant box add nginx nginx.box
I then create a new directory and use vagrant init nginx to create a new instance of the box. The whole process is described in this question.
When I use vagrant up, all appears to be running as expected:
vagrant up
Bringing machine 'default' up with 'virtualbox' provider...
==> default: Importing base box 'nginx'...
==> default: Matching MAC address for NAT networking...
==> default: Setting the name of the VM: Custom_default_1503826905856_10643
==> default: Clearing any previously set network interfaces...
==> default: Preparing network interfaces based on configuration...
default: Adapter 1: nat
default: Adapter 2: hostonly
==> default: Forwarding ports...
default: 22 (guest) => 2222 (host) (adapter 1)
==> default: Running 'pre-boot' VM customizations...
==> default: Booting VM...
==> default: Waiting for machine to boot. This may take a few minutes...
default: SSH address: 127.0.0.1:2222
default: SSH username: ubuntu
default: SSH auth method: password
==> default: Machine booted and ready!
==> default: Checking for guest additions in VM...
==> default: Configuring and enabling network interfaces...
==> default: Mounting shared folders...
default: /vagrant => /home/blackslate/repos/Vagrant/Custom
However, vagrant ssh provokes the message at the beginning of this question. When I try to ssh in manually, using "ubuntu" as the ssh user and "vagrant" as the password, I get this:
ssh ubuntu#127.0.0.1
The authenticity of host '127.0.0.1 (127.0.0.1)' can't be established.
ECDSA key fingerprint is SHA256:PSnauymZfKi1HIRIKfez5wAnpPFJW9h3eC+TzxiiIWA.
Are you sure you want to continue connecting (yes/no)? y
Please type 'yes' or 'no': yes
Warning: Permanently added '127.0.0.1' (ECDSA) to the list of known hosts.
ubuntu#127.0.0.1's password:
Permission denied, please try again.
ubuntu#127.0.0.1's password:
I get a similar result if I try ssh vagrant#127.0.0.1:
ssh vagrant#127.0.0.1
vagrant#127.0.0.1's password:
Permission denied, please try again.
vagrant#127.0.0.1's password:
The same is true if I open the VirtualBox GUI and talk to the VM directly.
I have tried following the instructions here, but I'm guessing that this refers to an older version of Vagrant.
I am hoping that I will be able to make changes at the package stage, so that when I distribute the custom Vagrant box to other developers, vagrant ssh just works, with no need to massage any files beforehand.

Answer 1

Try using the Oracle Virtual Box Manager to log in directly console instead of with ssh. Thereupon may edit the sshd config file and allow the passoword authentication. Restart SSHD service.