Getting Hetzner Storage Box to work on kube-hetzner

[WebSpider]

I have a small cluster but expecting some growth, and have a half-filled storage-box around, so I thought I'd enable the SMB CSI, and setup a StorageClass.

This turned out to be easier said than done. I know the StorageBox config works, since I can mount it from my Ubuntu 22 laptop just fine ... but using the same credentials, the control plane VM only complains about:

cluster1-cp-hel1-xve:/tmp # mount -t cifs --verbose //my.your-storagebox.de/uSNIP-sub2 /tmp/test -o vers=3.0,workgroup=WORKGROUP,username=uSNIP-sub2,password=s3cr3t,dir_mode=0777,file_mode=0777,cache=strict,actimeo=30
mount.cifs kernel mount options: ip=x.y.z,unc=\\my.your-storagebox.de\uSNIP-sub2,vers=3.0,dir_mode=0777,file_mode=0777,cache=strict,actimeo=30,user=uSNIP-sub2,domain=WORKGROUP,pass=********
mount error(115): Operation now in progress
Refer to the mount.cifs(8) manual page (e.g. man mount.cifs) and kernel log messages (dmesg)

Has anyone managed to get this to work?