BACK UP WEBSITE - sudo: export: command not found

I tried upgrading using

sh <(curl https://raw.githubusercontent.com/usmannasir/cyberpanel/stable/preUpgrade.sh || wget -O - https://raw.githubusercontent.com/usmannasir/cyberpanel/stable/preUpgrade.sh)

After doing so I reboot server and then unable to access anything, no SSH access etc, had to resort to restoring using a snaphot.

Any ideas please