PROBLEM: Can´t backup VMs anymore

[carl]

Mira, well, for what it's worth: These are the last two lines in the hook script in question:

...
proxmox-backup-client backup root.pxar:/ --all-file-systems --backup-type host
proxmox-backup-client logout

I doubt that the hook script is faulty. But, rather, that the proxmox-backup-client logout is causing the problem

proxmox-backup-client logout is the culprit. With that line commented out the backup completes without errors.