Helm install fails

I like to install xwiki helm on kubernetes/rancher.
First i had Problems because our default storage class does not support readwritemany.
So i installed longhorn, set it to the default storage class because storageClassName: “longhorn” in the values.yaml is not working.

The pvc is mounted in Rancher but xwiki is not able to use it

I get the Error
mount failed: exit status 32
bad option; for several filesystems (e.g. nfs, cifs) you might need a /sbin/mount. helper program.