NFS mount operation not permitted

[Strux]

Setup: Running OMV (192.168.1.59) in a Proxmox VM with two merged disks. Shared folder is created, NFS is enabled and my W10 laptop can connect to it.
On same Proxmox node i run a privileged Docker compose LXC with a Jellyfin container (192.168.1.50). NFS is enabled, nfs-common is installed and it already has a NFS mount to my synology NAS. This has been done inside the Jellyfin container, (because i read somewhere that it would be the most direct route) with the mount command, not with /etc/fstab, because it doesn't exist inside an LXC. Idk if what i did was innovative or braindead.

Objective: If it isn't obvious, i would like my Jellyfin LXC to mount the shared folder from the OMV VM

Problem: When i try to mount the shared folder with the following command:
mount -o ro,nolock,vers=4 192.168.1.59:/export/ /mnt/omv-media -vvv
I get the following output:
mount.nfs: timeout set for Fri May 10 08:34:35 2024
mount.nfs: trying text-based options 'nolock,vers=4,addr=192.168.1.59,clientaddr=192.168.1.50'
mount.nfs: mount(2): Operation not permitted
mount.nfs: trying text-based options 'nolock,addr=192.168.1.59'
mount.nfs: prog 100003, trying vers=3, prot=6
mount.nfs: trying 192.168.1.59 prog 100003 vers 3 prot TCP port 2049
mount.nfs: prog 100005, trying vers=3, prot=17
mount.nfs: trying 192.168.1.59 prog 100005 vers 3 prot UDP port 51819
mount.nfs: Protocol not supported

I use /export, because i read somewhere that that's where the shared folder would be. I also tried these commands:
mount 192.168.1.59:/ /mnt/omv-media
mount -o ro,nolock,vers=4 192.168.1.59:/export/ /mnt/omv-media
mount -o rw,nolock,vers=3 192.168.1.59:/ /mnt/omv-media

but with more or less the same output. In OMV syslog, i cannot see any denied attempts to connect, which i usually can, so i guess it has nothing to do with OMV.
In OMV VM's /etc/exports:
/export/omv-media 192.168.1.0/24
/export 192.168.1.0/24(ro,fsid=0,root_squash,no_subtree_check)

It really annoys me that the shared folder from OMV should work, since my W10 can mount it and the NFS capabilities on Jellyfin LXC should also work, since it already has a NFS mount.
Also, i have trouble finding what "Operation not permitted" means exactly. I've searched around and found a lot of root causes for this error, but none that fits my case as far as i can tell. Any input would be highly appreciated.

Thank you in advance

[TheDreadPirate]

Do you HAVE to use the NFS share for Jellyfin? If the storage is on the same machine and not virtualized, couldn't the LXC just directly access the volume with the media? (I have never used Proxmox)

If not, it would probably be better to mount the NFS share in Proxmox and pass that in as a volume in the docker compose. Let the host handle NFS. You could also mount the NFS share in the docker compose and pass it in as a volume.

https://forums.docker.com/t/docker-compo.../132551/11