i write sudo apt-get update
and the ubuntu show me
E: The repository 'cdrom://Lubuntu 20.04.4 LTS _Focal Fossa_ - Release amd64 (20220223) focal Release' does not have 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.
error. how to fix it?!