Centos – Yum Updateが失敗する：エラー：リポジトリのリポジトリメタデータ（repomd.xml）を取得できません…？

CentOS6.3を使用しています。システムをyumで更新しようとすると、次のメッセージが表示されます。

yum update

Loaded plugins: fastestmirror
Loading mirror speeds from cached hostfile
 * base: mirrors.ircam.fr
 * centosplus: miroir.univ-paris13.fr
 * extras: mirrors.ircam.fr
 * update: centos.quelquesmots.fr
http://mirror.centos.org/centos/6/addons/x86_64/repodata/repomd.xml: [Errno 14] PYCURL ERROR 22 - "The requested URL returned error: 404"
Trying other mirror.
Error: Cannot retrieve repository metadata (repomd.xml) for repository: addons. Please verify its path and try again

yum clean all

Loaded plugins: fastestmirror
Cleaning repos: CactiEZ addons base centosplus extras pgdg93 update
Cleaning up Everything
Cleaning up list of fastest mirrors

yum check

Loaded plugins: fastestmirror
check all

yum erase apf

Loaded plugins: fastestmirror
Setting up Remove Process
No Match for argument: apf
Determining fastest mirrors
 * base: centos.mirror.fr.planethoster.net
 * centosplus: centos.mirror.fr.planethoster.net
 * extras: mirrors.ircam.fr
 * update: centos.quelquesmots.fr
CactiEZ                                                | 2.9 kB     00:00
CactiEZ/primary_db                                     |  13 kB     00:00
http://mirror.centos.org/centos/6/addons/x86_64/repodata/repomd.xml: [Errno 14] PYCURL ERROR 22 - "The requested URL returned error: 404"
Trying other mirror.
Error: Cannot retrieve repository metadata (repomd.xml) for repository: addons. Please verify its path and try again

yum upgrade

Loaded plugins: fastestmirror
Loading mirror speeds from cached hostfile
 * base: centos.mirror.fr.planethoster.net
 * centosplus: centos.mirror.fr.planethoster.net
 * extras: mirrors.ircam.fr
 * update: centos.quelquesmots.fr
http://mirror.centos.org/centos/6/addons/x86_64/repodata/repomd.xml: [Errno 14] PYCURL ERROR 22 - "The requested URL returned error: 404"
Trying other mirror.
Error: Cannot retrieve repository metadata (repomd.xml) for repository: addons. Please verify its path and try again

私のyum.conf

[main]
cachedir=/var/cache/yum/$basearch/$releasever
keepcache=0
debuglevel=2
logfile=/var/log/yum.log
exactarch=1
obsoletes=1
gpgcheck=1
plugins=1
installonly_limit=5
bugtracker_url=http://bugs.centos.org/set_project.php?project_id=16&ref=http://bugs.centos.org/bug_report_page.php?category=yum
distroverpkg=centos-release

承認された回答：

ca-bundles.crtが古すぎます。 CentOSの新しいバージョンにアップグレードするまでの回避策の1つは、epel.repoをhttpsからhttp

に変更することです。

sudo sed -i 's/https/http/g' /etc/yum.repos.d/epel.repo