昨天一切都很好，sudo apt-get update运行良好，但今天它不工作了，只是说无法连接到不同的网站。
然后我尝试在软件和更新中更改服务器，它甚至找不到一个可以连接的服务器。
浏览器工作正常，也ping google.com工作正常，但ping6 google.com不起作用。
我正在使用 ubuntu 14.04
提前致谢！
更新：
这是我的来源列表：
# deb cdrom:[Ubuntu 14.04.6 LTS _Trusty Tahr_ - Release amd64 (20190304.5)]/ 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 trusty main restricted
deb-src http://archive.ubuntu.com/ubuntu trusty main restricted
## Major bug fix updates produced after the final release of the
## distribution.
deb http://archive.ubuntu.com/ubuntu trusty-updates main restricted
deb-src http://archive.ubuntu.com/ubuntu trusty-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 trusty universe
deb-src http://archive.ubuntu.com/ubuntu trusty universe
deb http://archive.ubuntu.com/ubuntu trusty-updates universe
deb-src http://archive.ubuntu.com/ubuntu trusty-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 trusty multiverse
deb-src http://archive.ubuntu.com/ubuntu trusty multiverse
deb http://archive.ubuntu.com/ubuntu trusty-updates multiverse
deb-src http://archive.ubuntu.com/ubuntu trusty-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 trusty-backports main restricted universe multiverse
deb-src http://archive.ubuntu.com/ubuntu trusty-backports main restricted universe multiverse
deb http://archive.ubuntu.com/ubuntu trusty-security main restricted
deb-src http://archive.ubuntu.com/ubuntu trusty-security main restricted
deb http://archive.ubuntu.com/ubuntu trusty-security universe
deb-src http://archive.ubuntu.com/ubuntu trusty-security universe
deb http://archive.ubuntu.com/ubuntu trusty-security multiverse
deb-src http://archive.ubuntu.com/ubuntu trusty-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
## This software is not part of Ubuntu, but is offered by third-party
## developers who want to ship their latest software.
# deb http://extras.ubuntu.com/ubuntu trusty main
# deb-src http://extras.ubuntu.com/ubuntu trusty main
deb http://archive.ubuntu.com/ubuntu trusty-proposed restricted universe main multiverse
答案1
转到软件和更新选择其他软件取消选中所有 ppas 单击关闭单击重新加载
转到 Lite 欢迎
祝你好运！