fatal error/crash on "unable to install grub"

[matari ganan]

before install: My computer has dual boot for windows 10 and OpenSUSE 15.2
Under my Primary partition SDA3, I have logical partitions...
sda6: for OpenSUSE OS
sda7: for swap file
sda8: for /home

I tried adding as logical partitions
sda9: for Xubuntu
sda10: for swap file &
sda11: for /home

ProblemType: Bug
DistroRelease: Ubuntu 20.10
Package: ubiquity 20.10.13
ProcVersionSignature: Ubuntu 5.8.0-25.26-generic 5.8.14
Uname: Linux 5.8.0-25-generic x86_64
NonfreeKernelModules: zfs zunicode zavl icp zcommon znvpair
ApportVersion: 2.20.11-0ubuntu50
Architecture: amd64
CasperMD5CheckResult: pass
CasperVersion: 1.455
Date: Mon Nov 2 19:12:35 2020
InstallCmdLine: BOOT_IMAGE=/casper/vmlinuz file=/cdrom/preseed/xubuntu.seed maybe-ubiquity quiet splash ---
LiveMediaBuild: Xubuntu 20.10 "Groovy Gorilla" - Release amd64 (20201022)
ProcEnviron:
 LANGUAGE=en_US.UTF-8
 PATH=(custom, no user)
 XDG_RUNTIME_DIR=<set>
 LANG=en_US.UTF-8
 LC_NUMERIC=C.UTF-8
RebootRequiredPkgs:
 linux-image-5.8.0-26-generic
 linux-base
 linux-image-5.8.0-25-generic
 linux-base
SourcePackage: ubiquity
UpgradeStatus: No upgrade log present (probably fresh install)