Snap install fails

[marcoceppi]

ubuntu@webinar:~$ sudo snap install conjure-up --classic
error: cannot perform the following tasks:
- Run configure hook of "conjure-up" snap if present (run hook "configure": 
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+ [[ ! -x /snap/bin/lxd ]]
+ grep -q zesty /etc/lsb-release
+ apt-add-repository -y ppa:ubuntu-lxc/lxd-stable
gpg: keyring `/tmp/tmp28n24ibw/secring.gpg' created
gpg: keyring `/tmp/tmp28n24ibw/pubring.gpg' created
gpg: requesting key 7635B973 from hkp server keyserver.ubuntu.com
gpg: /tmp/tmp28n24ibw/trustdb.gpg: trustdb created
gpg: key 7635B973: public key "Launchpad PPA for Ubuntu LXC team" imported
gpg: Total number processed: 1
gpg:               imported: 1  (RSA: 1)
OK
+ apt-get -qq update
W: The repository 'http://ppa.launchpad.net/ubuntu-lxc/lxd-stable/ubuntu xenial Release' does not have a Release file.
E: Failed to fetch http://ppa.launchpad.net/ubuntu-lxc/lxd-stable/ubuntu/dists/xenial/main/binary-amd64/Packages  403  Forbidden
E: Some index files failed to download. They have been ignored, or old ones used instead.
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Provide the output of the following commands:

ubuntu@webinar:~$ which juju
ubuntu@webinar:~$ which conjure-up
ubuntu@webinar:~$ which lxd
/usr/bin/lxd
ubuntu@webinar:~$ juju version
The program 'juju' can be found in the following packages:
 * juju-2.0
 * juju-1-default
Try: sudo apt install <selected package>
ubuntu@webinar:~$ conjure-up --version
The program 'conjure-up' is currently not installed. You can install it by typing:
sudo apt install conjure-up
ubuntu@webinar:~$ lxd --version
2.0.9
ubuntu@webinar:~$ cat /etc/lsb-release
DISTRIB_ID=Ubuntu
DISTRIB_RELEASE=16.04
DISTRIB_CODENAME=xenial
DISTRIB_DESCRIPTION="Ubuntu 16.04.2 LTS"

Summary of problem: