Множество «Err: временное устранение сбоев» и «W: Failed to fetch» ​​при запуске apt-get update [duplicate]

Я получаю эту ошибку при запуске apt-get update .

root@server1:~# sudo apt-get update
Err:1 http://apt.izzysoft.de/ubuntu generic InRelease
  Temporary failure resolving 'apt.izzysoft.de'
Err:2 http://ppa.launchpad.net/ondrej/apache2/ubuntu xenial InRelease
  Temporary failure resolving 'ppa.launchpad.net'
Err:3 http://apt.newrelic.com/debian newrelic InRelease
  Temporary failure resolving 'apt.newrelic.com'
Err:4 http://software.virtualmin.com/gpl/ubuntu virtualmin-xenial InRelease
  Temporary failure resolving 'software.virtualmin.com'
Err:5 http://ppa.launchpad.net/ondrej/php/ubuntu xenial InRelease
  Temporary failure resolving 'ppa.launchpad.net'
Err:6 http://security.ubuntu.com/ubuntu xenial-security InRelease
  Temporary failure resolving 'security.ubuntu.com'
Err:7 http://software.virtualmin.com/gpl/ubuntu virtualmin-universal InRelease
  Temporary failure resolving 'software.virtualmin.com'
Err:8 http://archive.ubuntu.com/ubuntu xenial InRelease
  Temporary failure resolving 'archive.ubuntu.com'
Err:9 https://deb.nodesource.com/node_4.x xenial InRelease
  Could not resolve host: deb.nodesource.com
Err:10 http://archive.ubuntu.com/ubuntu xenial-updates InRelease
  Temporary failure resolving 'archive.ubuntu.com'
Err:11 http://archive.ubuntu.com/ubuntu xenial-backports InRelease
  Temporary failure resolving 'archive.ubuntu.com'
Reading package lists... Done
W: Failed to fetch http://archive.ubuntu.com/ubuntu/dists/xenial/InRelease  Temporary failure resolving 'archive.ubuntu.com'
W: Failed to fetch http://archive.ubuntu.com/ubuntu/dists/xenial-updates/InRelease  Temporary failure resolving 'archive.ubuntu.com'
W: Failed to fetch http://archive.ubuntu.com/ubuntu/dists/xenial-backports/InRelease  Temporary failure resolving 'archive.ubuntu.com'
W: Failed to fetch http://security.ubuntu.com/ubuntu/dists/xenial-security/InRelease  Temporary failure resolving 'security.ubuntu.com'
W: Failed to fetch http://software.virtualmin.com/gpl/ubuntu/dists/virtualmin-xenial/InRelease  Temporary failure resolving 'software.virtualmin.com'
W: Failed to fetch http://software.virtualmin.com/gpl/ubuntu/dists/virtualmin-universal/InRelease  Temporary failure resolving 'software.virtualmin.com'
W: Failed to fetch http://apt.izzysoft.de/ubuntu/dists/generic/InRelease  Temporary failure resolving 'apt.izzysoft.de'
W: Failed to fetch http://apt.newrelic.com/debian/dists/newrelic/InRelease  Temporary failure resolving 'apt.newrelic.com'
W: Failed to fetch https://deb.nodesource.com/node_4.x/dists/xenial/InRelease  Could not resolve host: deb.nodesource.com
W: Failed to fetch http://ppa.launchpad.net/ondrej/apache2/ubuntu/dists/xenial/InRelease  Temporary failure resolving 'ppa.launchpad.net'
W: Failed to fetch http://ppa.launchpad.net/ondrej/php/ubuntu/dists/xenial/InRelease  Temporary failure resolving 'ppa.launchpad.net'
W: Some index files failed to download. They have been ignored, or old ones used instead.

Есть предложения, что я могу сделать, чтобы это исправить?

Это мой /etc/apt/sources.list :

# deb cdrom:[Ubuntu-Server 14.04 LTS _Trusty Tahr_ - Release amd64 (20140416.2)]/ trusty main restricted

# deb cdrom:[Ubuntu-Server 14.04 LTS _Trusty Tahr_ - Release amd64 (20140416.2)]/ trusty main restricted

# See http://help.ubuntu.com/community/UpgradeNotes for how to upgrade to
# newer versions of the distribution.
deb http://archive.ubuntu.com/ubuntu/ xenial main restricted
deb-src http://archive.ubuntu.com/ubuntu/ xenial main restricted

## Major bug fix updates produced after the final release of the
## distribution.
deb http://archive.ubuntu.com/ubuntu/ xenial-updates main restricted
deb-src http://archive.ubuntu.com/ubuntu/ xenial-updates main restricted

## N.B. software from this repository is ENTIRELY UNSUPPORTED by the Ubuntu
## team. Also, please note that software in universe WILL NOT receive any
## review or updates from the Ubuntu security team.
deb http://archive.ubuntu.com/ubuntu/ xenial universe
deb-src http://archive.ubuntu.com/ubuntu/ xenial universe
deb http://archive.ubuntu.com/ubuntu/ xenial-updates universe
deb-src http://archive.ubuntu.com/ubuntu/ xenial-updates universe

## N.B. software from this repository is ENTIRELY UNSUPPORTED by the Ubuntu 
## team, and may not be under a free licence. Please satisfy yourself as to 
## your rights to use the software. Also, please note that software in 
## multiverse WILL NOT receive any review or updates from the Ubuntu
## security team.
deb http://archive.ubuntu.com/ubuntu/ xenial multiverse
deb-src http://archive.ubuntu.com/ubuntu/ xenial multiverse
deb http://archive.ubuntu.com/ubuntu/ xenial-updates multiverse
deb-src http://archive.ubuntu.com/ubuntu/ xenial-updates multiverse

## N.B. software from this repository may not have been tested as
## extensively as that contained in the main release, although it includes
## newer versions of some applications which may provide useful features.
## Also, please note that software in backports WILL NOT receive any review
## or updates from the Ubuntu security team.
deb http://archive.ubuntu.com/ubuntu/ xenial-backports main restricted universe multiverse
deb-src http://archive.ubuntu.com/ubuntu/ xenial-backports main restricted universe multiverse

deb http://security.ubuntu.com/ubuntu xenial-security main restricted
deb-src http://security.ubuntu.com/ubuntu xenial-security main restricted
deb http://security.ubuntu.com/ubuntu xenial-security universe
deb-src http://security.ubuntu.com/ubuntu xenial-security universe
deb http://security.ubuntu.com/ubuntu xenial-security multiverse
deb-src http://security.ubuntu.com/ubuntu xenial-security multiverse

## Uncomment the following two lines to add software from Canonical's
## 'partner' repository.
## This software is not part of Ubuntu, but is offered by Canonical and the
## respective vendors as a service to Ubuntu users.
# deb http://archive.canonical.com/ubuntu trusty partner
# deb-src http://archive.canonical.com/ubuntu trusty partner

## Uncomment the following two lines to add software from Ubuntu's
## 'extras' repository.