atmark@atde9:~$ sudo apt-get update
ヒット:1 http://security.debian.org/debian-security bullseye-security InRelease
エラー:2 https://packages.microsoft.com/repos/code stable InRelease                                               
  Certificate verification failed: The certificate is NOT trusted. The certificate issuer is unknown.  Could not handshake: Error in the certificate verification. [IP: 13.107.246.46 443]
無視:3 http://download.atmark-techno.com/debian bullseye InRelease                                                
ヒット:4 http://download.atmark-techno.com/debian bullseye Release                           
ヒット:5 http://ftp.jp.debian.org/debian bullseye InRelease
ヒット:6 http://ftp.jp.debian.org/debian bullseye-updates InRelease
パッケージリストを読み込んでいます... 完了
W: https://packages.microsoft.com/repos/code/dists/stable/InRelease の取得に失敗しました  Certificate verification failed: The certificate is NOT trusted. The certificate issuer is unknown.  Could not handshake: Error in the certificate verification. [IP: 13.107.246.46 443]
W: いくつかのインデックスファイルのダウンロードに失敗しました。これらは無視されるか、古いものが代わりに使われます。

atmark@atde9:~$ ls -l /etc/apt/sources.list
-rw-r--r-- 1 root root 814  9月 19 12:14 /etc/apt/sources.list

atmark@atde9:~$ cat /etc/apt/sources.list
# deb cdrom:[Debian GNU/Linux 11.11.0 _Bullseye_ - Official amd64 DVD Binary-1 20240831-14:01]/ bullseye contrib main

# deb cdrom:[Debian GNU/Linux 11.11.0 _Bullseye_ - Official amd64 DVD Binary-1 20240831-14:01]/ bullseye contrib main

deb http://ftp.jp.debian.org/debian/ bullseye main non-free
deb-src http://ftp.jp.debian.org/debian/ bullseye main

deb http://security.debian.org/debian-security bullseye-security main contrib
deb-src http://security.debian.org/debian-security bullseye-security main contrib

# bullseye-updates, to get updates before a point release is made;
# see https://www.debian.org/doc/manuals/debian-reference/ch02.en.html#_updates_and_backports
deb http://ftp.jp.debian.org/debian/ bullseye-updates main contrib
deb-src http://ftp.jp.debian.org/debian/ bullseye-updates main contrib