Linux Mastering Development Ubuntu

Issue installing Lubuntu 20.04 [duplicate]

When I try to install Lubuntu this appears: Command apt-get update finished with exit code 100. Output: ign:1 cdrom://Lubuntu 20.04 LTS_Focal_Fossa_-Release amd64 (20200423) focal Release Reading package lists… E: Release file for cdrom:[Lubuntu 20.04 LTS_Focal Fossa_-Release amd64 (20200423)]/dists/focal/Release is not valid yet (invalid for another 20d 15h 28min 3s). Updates for this repository will not […]