Ubuntu is not supported by our licensing system, but the control panel licences may work in some environments for a limited time. If the server is fresh or have limited amount of data, It's recommended to re-install the OS as Almalinux 8.9. It will help to keep your services smooth and not disturbed by the unsupported OS conflictions

Here's a solution, But there's no guarantee if it will work for a longer time, Shifting to the supported OS as soon as possible will be the best option:

Execute them one-by-one:

rm -rf /usr/bin/RcLicense_plesk
rm -rf /usr/bin/RcLicensePlesk
rm -rf /usr/bin/RcLicense_Plesk
rm -rf /etc/cron.d/rcplesk
rm -rf /etc/cron.d/rcpleskbackup
rm -rf /etc/sw/keys/keys

Then update your OS:

sudo apt update && sudo apt upgrade

And resolve any internal issues with Plesk:

plesk repair all -y

And at last, refresh your license by this command:

slnPlesk

It will regenerate your Plesk key and you will be able to access the dashboard again