Standard setup failing with The repository 'http://security.ubuntu.com/ubuntu xenial-security Release' is no longer signed

Hi,

I am consistently getting failures from the vagrant up command.

beginning with
==> default: Bindfs seems to not be installed on the virtual machine, installing now
The following SSH command responded with a non-zero exit status.
Vagrant assumes that this means the command failed!

apt-get update

Stdout from the command:
Hit:1 http://archive.ubuntu.com/ubuntu xenial InRelease
Ign:2 http://security.ubuntu.com/ubuntu xenial-security InRelease
Ign:3 http://archive.ubuntu.com/ubuntu xenial-updates InRelease
Get:4 http://security.ubuntu.com/ubuntu xenial-security Release [106 kB]
Ign:5 http://archive.ubuntu.com/ubuntu xenial-backports InRelease
Err:6 http://security.ubuntu.com/ubuntu xenial-security Release.gpg
  500  Internal Server Error [IP: 91.189.91.26 80]
Get:7 http://archive.ubuntu.com/ubuntu xenial-updates Release [108 kB]
Get:8 http://archive.ubuntu.com/ubuntu xenial-backports Release [106 kB]
Err:9 http://archive.ubuntu.com/ubuntu xenial-updates Release.gpg
  500  Internal Server Error [IP: 91.189.88.161 80]
Err:10 http://archive.ubuntu.com/ubuntu xenial-backports Release.gpg
  500  Internal Server Error [IP: 91.189.88.161 80]
Reading package lists...


Stderr from the command:

E: The repository 'http://security.ubuntu.com/ubuntu xenial-security Release' is no longer signed.
E: The repository 'http://archive.ubuntu.com/ubuntu xenial-updates Release' is no longer signed.
E: The repository 'http://archive.ubuntu.com/ubuntu xenial-backports Release' is no longer signed.

I have just run this on a completely new directory. Lost, lost, lost.