upgrading from ubuntu 16.06 to 18.04 got this error

[noel]

Updating /boot/grub/menu.lst ... done

/etc/kernel/postinst.d/zz-update-grub:
Sourcing file `/etc/default/grub'
Sourcing file `/etc/default/grub.d/50-cloudimg-settings.cfg'
Generating grub configuration file ...
Found linux image: /boot/vmlinuz-4.15.0-171-generic
Found initrd image: /boot/initrd.img-4.15.0-171-generic
Found linux image: /boot/vmlinuz-4.4.0-210-generic
Found initrd image: /boot/initrd.img-4.4.0-210-generic
Found linux image: /boot/vmlinuz-4.4.0-209-generic
Found initrd image: /boot/initrd.img-4.4.0-209-generic
Found linux image: /boot/vmlinuz-4.4.0-206-generic
Found initrd image: /boot/initrd.img-4.4.0-206-generic
done
Processing triggers for sgml-base (1.29) ...
Processing triggers for resolvconf (1.79ubuntu10) ...
Errors were encountered while processing:
 shim-signed
Exception during pm.DoInstall(): E:Sub-process /usr/bin/dpkg returned an error code (1)

ProblemType: Package
DistroRelease: Ubuntu 18.04
Package: shim-signed 1.34.9+13-0ubuntu2
ProcVersionSignature: Ubuntu 4.4.0-210.242-generic 4.4.262
Uname: Linux 4.4.0-210-generic x86_64
.proc.sys.kernel.moksbstate_disabled: 0
ApportVersion: 2.20.9-0ubuntu7.27
Architecture: amd64
BootEFIContents:
 BOOTX64.CSV
 grub.cfg
 grubx64.efi
 mmx64.efi
 shimx64.efi
Date: Mon Mar 21 16:37:06 2022
EFIBootMgr: Error: command ['efibootmgr', '-v'] failed with exit code 2: EFI variables are not supported on this system.
EFITables:

ErrorMessage: installed shim-signed package post-installation script subprocess returned error exit status 1
Python3Details: /usr/bin/python3.6, Python 3.6.9, python3-minimal, 3.6.5-3
PythonDetails: /usr/bin/python2.7, Python 2.7.17, python-minimal, 2.7.15~rc1-1
RelatedPackageVersions:
 dpkg 1.19.0.5ubuntu2
 apt 1.6.12ubuntu0.2
SourcePackage: shim-signed
Title: package shim-signed 1.34.9+13-0ubuntu2 failed to install/upgrade: installed shim-signed package post-installation script subprocess returned error exit status 1
UpgradeStatus: Upgraded to bionic on 2022-03-21 (0 days ago)

[Steve Langasek (vorlon)]

You are trying to upgrade to the release version of shim-signed instead of the version in bionic-updates. This is unsupported. Please fix your system configuration to include package fixes that were made available after Ubuntu 18.04 was released by enabling bionic-updates in your apt sources.