当我在服务器上使用 sudo apt-get udate 时，突然出现获取失败的情况，我不确定应该更改什么来修复此错误？我正在运行 ubuntu 14.04 LTS 服务器
daniel@rproxy:~$ sudo apt-get update
Ign http://dk.archive.ubuntu.com trusty InRelease
Hit http://dk.archive.ubuntu.com trusty-updates InRelease
Hit http://dk.archive.ubuntu.com trusty-backports InRelease
Hit http://dk.archive.ubuntu.com trusty Release.gpg
Hit http://dk.archive.ubuntu.com trusty-updates/main Sources
Hit http://dk.archive.ubuntu.com trusty-updates/restricted Sources
Hit http://dk.archive.ubuntu.com trusty-updates/universe Sources
Ign http://ppa.launchpad.net trusty InRelease
Hit http://dk.archive.ubuntu.com trusty-updates/multiverse Sources
Hit http://dk.archive.ubuntu.com trusty-updates/main amd64 Packages
Hit http://dk.archive.ubuntu.com trusty-updates/restricted amd64 Packages
Hit http://dk.archive.ubuntu.com trusty-updates/universe amd64 Packages
Hit http://dk.archive.ubuntu.com trusty-updates/multiverse amd64 Packages
Ign http://ppa.launchpad.net trusty InRelease
Hit http://dk.archive.ubuntu.com trusty-updates/main i386 Packages
Hit http://dk.archive.ubuntu.com trusty-updates/restricted i386 Packages
Hit http://dk.archive.ubuntu.com trusty-updates/universe i386 Packages
Hit http://dk.archive.ubuntu.com trusty-updates/multiverse i386 Packages
Hit http://dk.archive.ubuntu.com trusty-updates/main Translation-en
Ign http://ppa.launchpad.net trusty Release.gpg
Hit http://dk.archive.ubuntu.com trusty-updates/multiverse Translation-en
Hit http://ppa.launchpad.net trusty Release.gpg
Hit http://dk.archive.ubuntu.com trusty-updates/restricted Translation-en
Ign http://ppa.launchpad.net trusty Release
Hit http://dk.archive.ubuntu.com trusty-updates/universe Translation-en
Hit http://dk.archive.ubuntu.com trusty Release
Hit http://dk.archive.ubuntu.com trusty-backports/main Sources
Hit http://dk.archive.ubuntu.com trusty-backports/restricted Sources
Hit http://ppa.launchpad.net trusty Release
Hit http://dk.archive.ubuntu.com trusty-backports/universe Sources
Hit http://dk.archive.ubuntu.com trusty-backports/multiverse Sources
Hit http://dk.archive.ubuntu.com trusty-backports/main amd64 Packages
Hit http://dk.archive.ubuntu.com trusty-backports/restricted amd64 Packages
Hit http://dk.archive.ubuntu.com trusty-backports/universe amd64 Packages
Hit http://dk.archive.ubuntu.com trusty-backports/multiverse amd64 Packages
Hit http://dk.archive.ubuntu.com trusty-backports/main i386 Packages
Hit http://dk.archive.ubuntu.com trusty-backports/restricted i386 Packages
Hit http://dk.archive.ubuntu.com trusty-backports/universe i386 Packages
Hit http://dk.archive.ubuntu.com trusty-backports/multiverse i386 Packages
Hit http://dk.archive.ubuntu.com trusty-backports/main Translation-en
Hit http://dk.archive.ubuntu.com trusty-backports/multiverse Translation-en
Ign http://apt.puppetlabs.com trusty InRelease
Hit http://dk.archive.ubuntu.com trusty-backports/restricted Translation-en
Hit http://dk.archive.ubuntu.com trusty-backports/universe Translation-en
Ign http://download.draios.com stable-amd64/ InRelease
Hit http://ppa.launchpad.net trusty/main amd64 Packages
Hit http://dk.archive.ubuntu.com trusty/main Sources
Hit http://dk.archive.ubuntu.com trusty/restricted Sources
Hit http://dk.archive.ubuntu.com trusty/universe Sources
Hit http://dk.archive.ubuntu.com trusty/multiverse Sources
Hit http://dk.archive.ubuntu.com trusty/main amd64 Packages
Hit http://ppa.launchpad.net trusty/main i386 Packages
Hit http://dk.archive.ubuntu.com trusty/restricted amd64 Packages
Hit http://dk.archive.ubuntu.com trusty/universe amd64 Packages
Hit http://dk.archive.ubuntu.com trusty/multiverse amd64 Packages
Hit http://dk.archive.ubuntu.com trusty/main i386 Packages
Hit http://dk.archive.ubuntu.com trusty/restricted i386 Packages
Hit http://ppa.launchpad.net trusty/main Translation-en
Hit http://dk.archive.ubuntu.com trusty/universe i386 Packages
Hit http://dk.archive.ubuntu.com trusty/multiverse i386 Packages
Hit http://dk.archive.ubuntu.com trusty/main Translation-en
Hit http://dk.archive.ubuntu.com trusty/multiverse Translation-en
Hit http://apt.puppetlabs.com trusty Release.gpg
Hit http://download.draios.com stable-amd64/ Release.gpg
Hit http://dk.archive.ubuntu.com trusty/restricted Translation-en
Hit http://dk.archive.ubuntu.com trusty/universe Translation-en
Ign http://dk.archive.ubuntu.com trusty/main Translation-en_US
Ign http://dk.archive.ubuntu.com trusty/multiverse Translation-en_US
Ign http://dk.archive.ubuntu.com trusty/restricted Translation-en_US
Hit http://apt.puppetlabs.com trusty Release
Ign http://dk.archive.ubuntu.com trusty/universe Translation-en_US
Hit http://download.draios.com stable-amd64/ Release
Hit http://apt.puppetlabs.com trusty/main Sources
Hit http://download.draios.com stable-amd64/ Packages
Err http://ppa.launchpad.net trusty/main amd64 Packages
404 Not Found
Err http://ppa.launchpad.net trusty/main i386 Packages
404 Not Found
Ign http://ppa.launchpad.net trusty/main Translation-en_US
Hit http://apt.puppetlabs.com trusty/dependencies Sources
Ign http://ppa.launchpad.net trusty/main Translation-en
Hit http://apt.puppetlabs.com trusty/main amd64 Packages
Hit http://apt.puppetlabs.com trusty/dependencies amd64 Packages
Hit http://apt.puppetlabs.com trusty/main i386 Packages
Hit http://apt.puppetlabs.com trusty/dependencies i386 Packages
Hit http://security.ubuntu.com trusty-security InRelease
Ign http://download.draios.com stable-amd64/ Translation-en_US
Ign http://download.draios.com stable-amd64/ Translation-en
Hit http://security.ubuntu.com trusty-security/main Sources
Hit http://security.ubuntu.com trusty-security/restricted Sources
Hit http://security.ubuntu.com trusty-security/universe Sources
Hit http://security.ubuntu.com trusty-security/multiverse Sources
Hit http://security.ubuntu.com trusty-security/main amd64 Packages
Hit http://security.ubuntu.com trusty-security/restricted amd64 Packages
Ign http://apt.puppetlabs.com trusty/dependencies Translation-en_US
Ign http://apt.puppetlabs.com trusty/dependencies Translation-en
Hit http://security.ubuntu.com trusty-security/universe amd64 Packages
Ign http://apt.puppetlabs.com trusty/main Translation-en_US
Ign http://apt.puppetlabs.com trusty/main Translation-en
Hit http://security.ubuntu.com trusty-security/multiverse amd64 Packages
Hit http://security.ubuntu.com trusty-security/main i386 Packages
Hit http://security.ubuntu.com trusty-security/restricted i386 Packages
Hit http://security.ubuntu.com trusty-security/universe i386 Packages
Hit http://security.ubuntu.com trusty-security/multiverse i386 Packages
Hit http://security.ubuntu.com trusty-security/main Translation-en
Hit http://security.ubuntu.com trusty-security/multiverse Translation-en
Hit http://security.ubuntu.com trusty-security/restricted Translation-en
Hit http://security.ubuntu.com trusty-security/universe Translation-en
W: Failed to fetch http://ppa.launchpad.net/nginx/release/ubuntu/dists/trusty/main/binary-amd64/Packages 404 Not Found
W: Failed to fetch http://ppa.launchpad.net/nginx/release/ubuntu/dists/trusty/main/binary-i386/Packages 404 Not Found
E: Some index files failed to download. They have been ignored, or old ones used instead.
答案1
它无法工作，因为不再有 PPA release。删除列表文件：
grep -rl 'ppa.launchpad.net/nginx/release' /etc/apt | xargs sudo rm
sudo apt-get update
使用以下命令添加稳定版本 PPA
sudo apt-add-repository ppa:nginx/stable
sudo apt-get update
或其他Ngnix PPA。