When receiving an error mounting an NFS share inside your VM:
sudo mount -t nfs xxx.xxx.xxx.xxx:/data/media /mnt/nfs/media
mount.nfs: access denied by server while mounting xxx.xxx.xxx.xxx:/mnt/nfs/media
Just change the network adapter of your VM in VirtualBox from “NAT” to “Bridge Mode”.
As alternative you can force the usage of the TCP protocol when mounting, like it is described here.