Example of some error output:

dpkg: error processing package grub2-common
...
grub-pc depends on grub-common (= 2.04-1ubuntu26.13); however:
  Package grub-common is not configured yet.

...
No apport report written because MaxReports is reached already
                                                              No apport report written because MaxReports is reached already

Run this:

sudo apt-get purge grub\*
sudo apt-get install grub-efi
sudo apt-get autoremove
sudo update-grub

Go to rescue console/boot livecd depending on your environment.

If the server has raid 1 setup follow Reinstall grub on mdraid1 array

• Ubuntu 20.04.3

• Invalid environment block error
• Reinstall grub on mdraid1 array

• https://askubuntu.com/questions/1231781/errors-encountered-while-processing-grub-efi-amd64-signed-and-shim-signed-p