proxmox-backup-manager versions --verbose
root@pbs:~# proxmox-backup-manager versions --verbose
proxmox-backup 2.0-1 running kernel: 5.11.22-1-pve
proxmox-backup-server 2.0.4-1 running version: 2.0.4
pve-kernel-helper 7.0-4
pve-kernel-5.11 7.0-3
pve-kernel-5.11.22-1-pve 5.11.22-2
ifupdown2 3.0.0-1+pve5
libjs-extjs 7.0.0-1
proxmox-backup-docs 2.0.4-1
proxmox-backup-client 2.0.4-1
proxmox-mini-journalreader 1.2-1
proxmox-widget-toolkit 3.3-3
pve-xtermjs 4.12.0-1
smartmontools 7.2-1
zfsutils-linux 2.0.4-pve1
is not the newest version, and there were some fixes for tape libraries. so i'd suggest updating to the current versionproxmox-backup-server 2.0.4-1 running version: 2.0.4