I wrote the ISO to a couple of DVD-RW.
I tested the discs on 2 other machines, completely different motherboards, CPUs, DVD drivers.
One of them says
[FAILED] Failed to start Snap Daemon.Card State... submit kernel crash signature
[FAILED] Failed to start Ubuntu live CD installer.
One of them says
[FAILED] Failed to start Modem Manager.
[FAILED] Failed to start Snap Daemon.for details.d submit submit kernel crash signature
[FAILED] Failed to start Ubuntu live CD installer.
I also tried writing the ISO to a USB stick using some tool. Booting from the USB stick and installing Kubuntu 21.04 worked fine.
So, there is something specifically wrong with installing from DVD.
A couple of other people have the same problem. I haven't encountered a person for whom install from DVD worked.
Kubuntu 21.04
I wrote the ISO to a couple of DVD-RW.
I tested the discs on 2 other machines, completely different motherboards, CPUs, DVD drivers.
One of them says
[FAILED] Failed to start Snap Daemon.Card State... submit kernel crash signature
[FAILED] Failed to start Ubuntu live CD installer.
One of them says
[FAILED] Failed to start Modem Manager.
[FAILED] Failed to start Snap Daemon.for details.d submit submit kernel crash signature
[FAILED] Failed to start Ubuntu live CD installer.
I also tried writing the ISO to a USB stick using some tool. Booting from the USB stick and installing Kubuntu 21.04 worked fine.
So, there is something specifically wrong with installing from DVD.
A couple of other people have the same problem. I haven't encountered a person for whom install from DVD worked.