error on the intallation

[Felipe Nogueira Leite]

i was in the installation when apeared the error saying about my cd/rom, but he was unpluged and i donno what to do.

ProblemType: Bug
DistroRelease: Ubuntu 20.04
Package: ubiquity 20.04.15.10
ProcVersionSignature: Ubuntu 5.8.0-43.49~20.04.1-generic 5.8.18
Uname: Linux 5.8.0-43-generic x86_64
NonfreeKernelModules: zfs zunicode zavl icp zcommon znvpair
ApportVersion: 2.20.11-0ubuntu27.16
Architecture: amd64
CasperMD5CheckMismatches: ./casper/filesystem.squashfs
CasperMD5CheckResult: fail
CasperVersion: 1.445.1
CurrentDesktop: ubuntu:GNOME
Date: Sat May 15 10:57:41 2021
InstallCmdLine: file=/cdrom/preseed/ubuntu.seed initrd=/casper/initrd quiet splash --- maybe-ubiquity
LiveMediaBuild: Ubuntu 20.04.2.0 LTS "Focal Fossa" - Release amd64 (20210209.1)
ProcEnviron:
 LANGUAGE=en_US.UTF-8
 PATH=(custom, no user)
 XDG_RUNTIME_DIR=<set>
 LANG=en_US.UTF-8
 LC_NUMERIC=C.UTF-8
SourcePackage: ubiquity
UpgradeStatus: No upgrade log present (probably fresh install)

[Sebastien Bacher (seb128)]

 Thank you for taking the time to report this bug and helping to make Ubuntu better. While we appreciate the difficulties you are facing, it would appear that the image (ISO file) you downloaded could be corrupt. There is an easy way to verify the integrity of the Ubuntu ISO files you download. Could you please visit https://help.ubuntu.com/community/HowToMD5SUM follow the instructions and report back as to whether or not the MD5SUM verified? Thanks in advance.

The report includes this information

 CasperMD5CheckMismatches: ./casper/filesystem.squashfs