ubuntu 16.04源错误，谢谢了？

glenshappy 2018-01-18 09:24:35

我用的是ubuntu 16.04的版本（4.4.0-64-generic），最近使用apt-get update的时候，还有安装一些软件的时候，总是报下面的错，请问一下这位是什么问题呢？搞了一天了，试过很多办法，都不行
报错信息：
W: The repository 'http://extras.ubuntu.com/ubuntu xenial Release' does not have a Release file.
N: Data from such a repository can't be authenticated and is therefore potentially dangerous to use.
N: See apt-secure(8) manpage for repository creation and user configuration details.
W: http://nginx.org/packages/ubuntu/dists/lucid/Release.gpg: Signature by key 573BFD6B3D8FBC641079A6ABABF5BD827BD9BF62 uses weak digest algorithm (SHA1)
W: GPG error: http://nginx.org/packages/ubuntu lucid Release: The following signatures were invalid: KEYEXPIRED 1471427554
W: The repository 'http://nginx.org/packages/ubuntu lucid Release' is not signed.
N: Data from such a repository can't be authenticated and is therefore potentially dangerous to use.
N: See apt-secure(8) manpage for repository creation and user configuration details.
E: Failed to fetch http://extras.ubuntu.com/ubuntu/dists/xenial/main/binary-amd64/Packages 404 Not Found [IP: 91.189.92.152 80]
E: Some index files failed to download. They have been ignored, or old ones used instead.

/etc/apt/sources.list:
deb http://mirrors.aliyun.com/ubuntu/ xenial main restricted universe multiverse
deb http://mirrors.aliyun.com/ubuntu/ xenial-security main restricted universe multiverse
deb http://mirrors.aliyun.com/ubuntu/ xenial-updates main restricted universe multiverse
deb http://mirrors.aliyun.com/ubuntu/ xenial-backports main restricted universe multiverse
##测试版源
deb http://mirrors.aliyun.com/ubuntu/ xenial-proposed main restricted universe multiverse
# 源码
deb-src http://mirrors.aliyun.com/ubuntu/ xenial main restricted universe multiverse
deb-src http://mirrors.aliyun.com/ubuntu/ xenial-security main restricted universe multiverse
deb-src http://mirrors.aliyun.com/ubuntu/ xenial-updates main restricted universe multiverse
deb-src http://mirrors.aliyun.com/ubuntu/ xenial-backports main restricted universe multiverse
##测试版源
deb-src http://mirrors.aliyun.com/ubuntu/ xenial-proposed main restricted universe multiverse
# Canonical 合作伙伴和附加
deb http://archive.canonical.com/ubuntu/ xenial partner
deb http://extras.ubuntu.com/ubuntu/ xenial main

/etc/apt/sources.list.d/alternative_Repo.list:[color=#FF0000][/color]
# deb http://mirrors.aliyun.com/ubuntu/ xenial main restricted
# deb-src http://mirrors.aliyun.com/ubuntu/ xenial main restricted

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