Installation completed 99%, but aborted due to some technical error as reported in log file

Installation completed 99%, but aborted due to some technical error as reported in detail in log file,

Its 5th attempt to install, but unable to do the same

Please rectify the error.. give me a solution.

ProblemType: Bug
DistroRelease: Ubuntu 18.04
Package: ubiquity 18.04.14.15 [modified: usr/lib/ubiquity/user-setup/user-setup-apply usr/share/ubiquity/apt-setup]
ProcVersionSignature: Ubuntu 5.3.0-53.47~18.04.1-generic 5.3.18
Uname: Linux 5.3.0-53-generic x86_64
ApportVersion: 2.20.9-0ubuntu7.18
Architecture: amd64
CasperVersion: 1.394.3
Date: Thu Jan 21 17:22:22 2021
InstallCmdLine: BOOT_IMAGE=/casper/vmlinuz file=/cdrom/preseed/custom.seed boot=casper initrd=/casper/initrd.gz quiet splash --
LiveMediaBuild: Custom 18.04 - Release amd64
SourcePackage: ubiquity
UpgradeStatus: No upgrade log present (probably fresh install)