我在以下过程中收到此错误apt-get update：
W: Target Packages (main/binary-amd64/Packages) is configured multiple times in /etc/apt/sources.list.d/pgdg.list:1 and /etc/apt/sources.list.d/pgdg.list:2
W: Target Packages (main/binary-i386/Packages) is configured multiple times in /etc/apt/sources.list.d/pgdg.list:1 and /etc/apt/sources.list.d/pgdg.list:2
W: Target Packages (main/binary-all/Packages) is configured multiple times in /etc/apt/sources.list.d/pgdg.list:1 and /etc/apt/sources.list.d/pgdg.list:2
W: Target Translations (main/i18n/Translation-en_US) is configured multiple times in /etc/apt/sources.list.d/pgdg.list:1 and /etc/apt/sources.list.d/pgdg.list:2
W: Target Translations (main/i18n/Translation-en) is configured multiple times in /etc/apt/sources.list.d/pgdg.list:1 and /etc/apt/sources.list.d/pgdg.list:2
W: Target DEP-11 (main/dep11/Components-amd64.yml) is configured multiple times in /etc/apt/sources.list.d/pgdg.list:1 and /etc/apt/sources.list.d/pgdg.list:2
W: Target DEP-11-icons (main/dep11/icons-64x64.tar) is configured multiple times in /etc/apt/sources.list.d/pgdg.list:1 and /etc/apt/sources.list.d/pgdg.list:2
W: Failed to fetch http://ir.archive.ubuntu.com/ubuntu/dists/xenial/InRelease Could not connect to 127.0.0.1:8123 (127.0.0.1). - connect (111: Connection refused)
W: Failed to fetch http://ir.archive.ubuntu.com/ubuntu/dists/xenial-updates/InRelease Unable to connect to 127.0.0.1:8123:
W: Failed to fetch http://ir.archive.ubuntu.com/ubuntu/dists/xenial-backports/InRelease Unable to connect to 127.0.0.1:8123:
W: Failed to fetch http://security.ubuntu.com/ubuntu/dists/xenial-security/InRelease Could not connect to 127.0.0.1:8123 (127.0.0.1). - connect (111: Connection refused)
W: Failed to fetch https://download.sublimetext.com/apt/stable/InRelease Failed to connect to 127.0.0.1 port 8123: Connection refused
W: Failed to fetch https://ftp.ussg.iu.edu/CRAN/bin/linux/ubuntu/xenial/InRelease Failed to connect to 127.0.0.1 port 8123: Connection refused
W: Failed to fetch http://ppa.launchpad.net/deadsnakes/ppa/ubuntu/dists/xenial/InRelease Could not connect to 127.0.0.1:8123 (127.0.0.1). - connect (111: Connection refused)
W: Failed to fetch http://ppa.launchpad.net/george-edison55/cmake-3.x/ubuntu/dists/xenial/InRelease Unable to connect to 127.0.0.1:8123:
W: Failed to fetch http://dl.google.com/linux/chrome/deb/dists/stable/InRelease Could not connect to 127.0.0.1:8123 (127.0.0.1). - connect (111: Connection refused)
W: Failed to fetch http://ppa.launchpad.net/libreoffice/ppa/ubuntu/dists/xenial/InRelease Unable to connect to 127.0.0.1:8123:
W: Failed to fetch http://ppa.launchpad.net/noobslab/apps/ubuntu/dists/xenial/InRelease Unable to connect to 127.0.0.1:8123:
W: Failed to fetch http://ppa.launchpad.net/openjdk-r/ppa/ubuntu/dists/xenial/InRelease Unable to connect to 127.0.0.1:8123:
W: Failed to fetch http://ppa.launchpad.net/persepolis/ppa/ubuntu/dists/xenial/InRelease Unable to connect to 127.0.0.1:8123:
W: Failed to fetch http://apt.postgresql.org/pub/repos/apt/dists/xenial-pgdg/InRelease Could not connect to 127.0.0.1:8123 (127.0.0.1). - connect (111: Connection refused)
W: Failed to fetch https://repo.skype.com/deb/dists/stable/InRelease Failed to connect to 127.0.0.1 port 8123: Connection refused
W: Failed to fetch http://ppa.launchpad.net/smathot/cogscinl/ubuntu/dists/xenial/InRelease Unable to connect to 127.0.0.1:8123:
W: Failed to fetch http://ppa.launchpad.net/umang/indicator-stickynotes/ubuntu/dists/xenial/InRelease Unable to connect to 127.0.0.1:8123:
W: Some index files failed to download. They have been ignored, or old ones used instead.
W: Target Packages (main/binary-amd64/Packages) is configured multiple times in /etc/apt/sources.list.d/pgdg.list:1 and /etc/apt/sources.list.d/pgdg.list:2
W: Target Packages (main/binary-i386/Packages) is configured multiple times in /etc/apt/sources.list.d/pgdg.list:1 and /etc/apt/sources.list.d/pgdg.list:2
W: Target Packages (main/binary-all/Packages) is configured multiple times in /etc/apt/sources.list.d/pgdg.list:1 and /etc/apt/sources.list.d/pgdg.list:2
W: Target Translations (main/i18n/Translation-en_US) is configured multiple times in /etc/apt/sources.list.d/pgdg.list:1 and /etc/apt/sources.list.d/pgdg.list:2
W: Target Translations (main/i18n/Translation-en) is configured multiple times in /etc/apt/sources.list.d/pgdg.list:1 and /etc/apt/sources.list.d/pgdg.list:2
W: Target DEP-11 (main/dep11/Components-amd64.yml) is configured multiple times in /etc/apt/sources.list.d/pgdg.list:1 and /etc/apt/sources.list.d/pgdg.list:2
W: Target DEP-11-icons (main/dep11/icons-64x64.tar) is configured multiple times in /etc/apt/sources.list.d/pgdg.list:1 and /etc/apt/sources.list.d/pgdg.list:2
就像etc/apt/sources.list这样：
# See http://help.ubuntu.com/community/UpgradeNotes for how to upgrade to
# newer versions of the distribution.
deb http://ir.archive.ubuntu.com/ubuntu/ xenial main restricted
# deb-src http://ir.archive.ubuntu.com/ubuntu/ xenial main restricted
## Major bug fix updates produced after the final release of the
## distribution.
deb http://ir.archive.ubuntu.com/ubuntu/ xenial-updates main restricted
# deb-src http://ir.archive.ubuntu.com/ubuntu/ xenial-updates main restricted
## 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
## universe WILL NOT receive any review or updates from the Ubuntu security
## team.
deb http://ir.archive.ubuntu.com/ubuntu/ xenial universe
# deb-src http://ir.archive.ubuntu.com/ubuntu/ xenial universe
deb http://ir.archive.ubuntu.com/ubuntu/ xenial-updates universe
# deb-src http://ir.archive.ubuntu.com/ubuntu/ xenial-updates universe
## 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://ir.archive.ubuntu.com/ubuntu/ xenial multiverse
# deb-src http://ir.archive.ubuntu.com/ubuntu/ xenial multiverse
deb http://ir.archive.ubuntu.com/ubuntu/ xenial-updates multiverse
# deb-src http://ir.archive.ubuntu.com/ubuntu/ xenial-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://ir.archive.ubuntu.com/ubuntu/ xenial-backports main restricted universe multiverse
# deb-src http://ir.archive.ubuntu.com/ubuntu/ xenial-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://security.ubuntu.com/ubuntu xenial-security main restricted
# deb-src http://security.ubuntu.com/ubuntu xenial-security main restricted
deb http://security.ubuntu.com/ubuntu xenial-security universe
# deb-src http://security.ubuntu.com/ubuntu xenial-security universe
deb http://security.ubuntu.com/ubuntu xenial-security multiverse
# deb-src http://security.ubuntu.com/ubuntu xenial-security multiverse
deb https://download.sublimetext.com/ apt/stable/
# deb-src https://download.sublimetext.com/ apt/stable/
deb https://ftp.ussg.iu.edu/CRAN/bin/linux/ubuntu xenial/
# deb-src https://ftp.ussg.iu.edu/CRAN/bin/linux/ubuntu xenial/
问题是什么？
更新：
我发现了问题，但我不知道如何解决它。问题是 apt-get 正在使用代理，而我没有在任何地方使用任何代理。我不知道confapt-get 使用了哪个文件