Debian 11 was EOL in August and the security repo, does not seem to be in archive, and things are still broken even with apt.
E: Failed to fetch http://deb.debian.org/debian-security/pool/updates/main/b/bind9/dnsutils_9.16.50-1%7edeb11u6_all.deb 404 Not Found [IP: 151.101.194.132 80]
E: Unable to fetch some archives, maybe run apt-get update or try with --fix-missing?
#/etc/apt/sources.list
deb http://debian.org/debian-security bullseye-security main
debian, repo, fixes, eoldebian, eol, august, archive, apt, fetch, http, deb, org, updates, bind, dnsutils_, edeb, _all, ip, unable, archives, update, achive, modify, etc, sources, bullseye,