root@ies:~# pct listcan't open '/sys/fs/cgroup/blkio///lxc/.....' - No such file or directory

upgrade proxmox5.4 to proxmox6

if yes, then try running pve-efiboot-tool kernel list to see the available/loaded kernels. check the output to see which kernel is selected.

pve-efiboot-tool refresh will copy found kernels and create boot entries.


afterwards you should be booting into the new kernel.