我想使用certbot-auto renew续订证书，但是它不起作用。我在输出中遇到一些错误：
...
Hit http://ppa.launchpad.net precise/main amd64 Packages
Get:3 http://repo.mongodb.org precise/mongodb-org/3.2 Release [3,464 B]
Err http://repo.mongodb.org precise/mongodb-org/3.2 Release
Hit http://downloads-distro.mongodb.org dist/10gen i386 Packages
Hit http://ppa.launchpad.net precise/main i386 Packages
Hit http://ppa.launchpad.net precise/main TranslationIndex
Hit http://repo.mongodb.org precise/mongodb-org/3.4 Release
Ign http://repo.mongodb.org precise/mongodb-org/3.4 Release
Ign http://repo.mongodb.org precise/mongodb-org/3.4/multiverse amd64 Packages/DiffIndex
Ign http://downloads-distro.mongodb.org dist/10gen TranslationIndex
Ign http://repo.mongodb.org precise/mongodb-org/3.4/multiverse TranslationIndex
Hit http://ppa.launchpad.net precise/main Translation-en
Hit http://ppa.launchpad.net precise/main Translation-en
Err http://ppa.launchpad.net precise/main Sources
404 Not Found
Err http://ppa.launchpad.net precise/main amd64 Packages
404 Not Found
Err http://ppa.launchpad.net precise/main i386 Packages
404 Not Found
Ign http://ppa.launchpad.net precise/main Translation-en_US
Ign http://ppa.launchpad.net precise/main Translation-en
Ign http://ppa.launchpad.net precise/main Translation-en_US.UTF-8
Hit http://repo.mongodb.org precise/mongodb-org/3.4/multiverse amd64 Packages
Ign http://downloads-distro.mongodb.org dist/10gen Translation-en_US
Ign http://downloads-distro.mongodb.org dist/10gen Translation-en
Ign http://downloads-distro.mongodb.org dist/10gen Translation-en_US.UTF-8
Ign http://repo.mongodb.org precise/mongodb-org/3.4/multiverse Translation-en_US
Ign http://repo.mongodb.org precise/mongodb-org/3.4/multiverse Translation-en
Ign http://repo.mongodb.org precise/mongodb-org/3.4/multiverse Translation-en_US.UTF-8
Fetched 1,603 B in 4s (322 B/s)
Reading package lists... Done
W: A error occurred during the signature verification. The repository is not updated and the previous index files will be used. GPG error: http://repo.mongodb.org precise/mongodb-org/3.2 Release: The following signatures were invalid: KEYEXPIRED 1507497109
W: GPG error: http://repo.mongodb.org precise/mongodb-org/3.4 Release: The following signatures were invalid: KEYEXPIRED 1515625755
W: Failed to fetch http://ppa.launchpad.net/certbot/certbot/ubuntu/dists/precise/main/source/Sources 404 Not Found
W: Failed to fetch http://ppa.launchpad.net/certbot/certbot/ubuntu/dists/precise/main/binary-amd64/Packages 404 Not Found
W: Failed to fetch http://ppa.launchpad.net/certbot/certbot/ubuntu/dists/precise/main/binary-i386/Packages 404 Not Found
W: Failed to fetch http://repo.mongodb.org/apt/ubuntu/dists/precise/mongodb-org/3.2/Release
W: Some index files failed to download. They have been ignored, or old ones used instead.
我也分别尝试过运行apt-get update，结果相似。因此，我一直在寻找一些答案，它似乎与sources.list有关。
这是我的sources.list内容
deb http://archive.ubuntu.com/ubuntu precise main restricted universe
deb http://archive.ubuntu.com/ubuntu precise-updates main restricted universe
deb http://security.ubuntu.com/ubuntu precise-security main restricted universe multiverse
deb http://archive.canonical.com/ubuntu precise partner
我的sources.list.d / certbot-certbot-precise.list
deb http://ppa.launchpad.net/certbot/certbot/ubuntu precise main
deb-src http://ppa.launchpad.net/certbot/certbot/ubuntu precise main
我不确定这是问题所在，并且我不知道我需要在sources.list中进行什么更改，因此任何建议将不胜感激。
谢谢！