Missing Release File

[stu holden]

pi@pihole:~ $ cat /etc/debian_version
11.7
pi@pihole:~ $ sudo apt-get update
Ign:1 http://archive.raspbian.org/raspbian stretch InRelease
Hit:2 http://raspbian.raspberrypi.org/raspbian bullseye InRelease
Hit:3 http://archive.raspberrypi.org/debian bullseye InRelease
Err:4 http://archive.raspbian.org/raspbian stretch Release
  404 Not Found [IP: 93.93.128.191 80]
Reading package lists... Done

E: The repository 'http://archive.raspbian.org/raspbian stretch Release' no longer has a Release file.

N: Updating from such a repository can't be done securely, and is therefore disabled by default.
N: See apt-secure(8) manpage for repository creation and user configuration details.