这看起来很奇怪，但只有在安克雷奇时才会发生。我正在尝试更新我的 Ubuntu 18.04 LTS 并发出“sudo apt update”，但这就是我得到的：
E: Failed to fetch http://security.ubuntu.com/ubuntu/dists/bionic-security/main/binary-amd64/Packages 403 Forbidden [IP: 91.189.91.38 80]
E: Failed to fetch http://us.archive.ubuntu.com/ubuntu/dists/bionic-updates/main/binary-amd64/Packages 403 Forbidden [IP: 91.189.91.38 80]
E: Failed to fetch http://us.archive.ubuntu.com/ubuntu/dists/bionic/universe/binary-i386/Packages 403 Forbidden [IP: 91.189.91.38 80]
E: Some index files failed to download. They have been ignored, or old ones used instead.`
这是全新安装，并且已在安克雷奇的不同虚拟机上尝试了多次，但出现了相同的错误。
我还尝试了加拿大的另一个镜像站点，但没有成功。
令人费解的是，我对我们在科罗拉多州的另一个网站做了同样的事情，而且进展顺利。有什么想法吗？
这是我的 /etc/apt/sources.list
## 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://us.archive.ubuntu.com/ubuntu/ bionic multiverse
# deb-src http://us.archive.ubuntu.com/ubuntu/ bionic multiverse
deb http://us.archive.ubuntu.com/ubuntu/ bionic-updates multiverse
# deb-src http://us.archive.ubuntu.com/ubuntu/ bionic-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://us.archive.ubuntu.com/ubuntu/ bionic-backports main restricted universe multiverse
# deb-src http://us.archive.ubuntu.com/ubuntu/ bionic-backports main restricted universe 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 bionic partner
# deb-src http://archive.canonical.com/ubuntu bionic partner
deb http://security.ubuntu.com/ubuntu bionic-security main restricted
# deb-src http://security.ubuntu.com/ubuntu bionic-security main restricted
deb http://security.ubuntu.com/ubuntu bionic-security universe
# deb-src http://security.ubuntu.com/ubuntu bionic-security universe
deb http://security.ubuntu.com/ubuntu bionic-security multiverse
# deb-src http://security.ubuntu.com/ubuntu bionic-security multiverse
答案1
这个命令修复了它：
sed -i s/http/ftp/ /etc/apt/sources.list && apt-get update