Proxmox 6.4-4 NFS server on container

[SoporteIB]

Hello,
we have an issue with a container on Proxmox 6.4-4. This container has a nfs server (is a PXE server) was working fine on Proxmox 5.4.
We add the option "lxc.aa_profile: unconfined" to the container configuration but with the update it does not work.
The container shows a warning:

root@fog:~# service nfs-kernel-server restart
[ ok ] Stopping NFS kernel daemon: mountd nfsd.
[ ok ] Unexporting directories for NFS kernel daemon....
[warn] Not starting NFS kernel daemon: no support in current kernel. ... (warning).

Could you help us with this issue?
Thanks