backup failed: exit code 11

Massive Proxmox newb but I have a Proxmox setup and my scheduled backups keep failing and i'm trying to figure out if my storage is in danger... this is from the error listed whereit shows that the backup had errors.. : "var/tmp/vzdumptmp395447_110' failed: exit code 11 INFO: Failed at...

I upgraded a pve cluster from v5 to v6 and added a PBS to it. Now I had backup 3 small lxc (<10G for disk usage), but meet error when big size disk lxc. the output: INFO: starting new backup job: vzdump 114 --mode snapshot --node xnode006 --compress zstd --remove 0 --storage pbsXPFnfs INFO...