Hyper V Cluster Lost CSV (c000020c) while Backup

Hi,

I have a Hyper V Cluster with 6 Nodes and CSV Disks (Fiber Channel). 2 Nics for Guest only and 2 Nics for all other traffic.

I do Backups with Veeam. But sometimes i get this Error while the backup is running:

Cluster Shared Volume 'Volume2' ('Cluster Disk 2') is no longer available on this node because of 'STATUS_CONNECTION_DISCONNECTED(c000020c)'. All I/O will temporarily be queued until a path to the volume is reestablished.

The Guest on the this note with the disk on the Cluster disk 2 are Restarting.

Someone have idea why my Note lost the Connection to the CSV?