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dyzamox pm messages are already notified, please wait until (and if) the recipient answers...
And please in future, write here, you may also get faster and better support from more experienced users...
As I said privately: difficult to say, but the screenshot says "not a bootable disk", so it seems a disk *is* found, but can't be booted somehow. If it's the only vm disk, something could have happened to it (maybe just the mbr), so you need to check:
I would boot with a live cd (ubuntu, sysresccd) and try to understand if the disk data is ok, and can be mounted, and it just need to restore or reinstall the mbr, maybe. Otherwise it could be worse. If the data is ok, you can temporarily copy it on other storage, reinstall the vm and restore data later.
try also "#qm start <vmid>" from the pve host command line: more error messages could reveal problems not visible at console level.
then also post more details about your cluster: pve version, vm config, output of pveversion.
Thanks.