This is the error im getting:
Failed to execute command 'export PATH=/bin:/sbin:/usr/bin:/usr/sbin:/usr/local/bin:/usr/local/sbin; export LANG=C; mount -v --source '/dev/disk/by-label/Datengrab' 2>&1' with exit code '21': modprobe: ERROR: ../libkmod/libkmod.c:586 kmod_search_moddep() could not open moddep file '/lib/modules/4.19.50-v7l+/modules.dep.bin' modprobe: FATAL: Module fuse not found in directory /lib/modules/4.19.50-v7l+ ntfs-3g-mount: fuse device is missing, try 'modprobe fuse' as root
I don't use OMV this days I just switched to just using docker on a linux machine.
What I can tell mounting NTFS on linux is a pain and should not be considered long term solution.
As for a suggestion, to me it looks like you are performing operation not with the root / admin user, try to ssh into your machine, with root user, locate the hadd under cd /srv if it is there, mount it and see if it mounts of gives you an error.