Cannot mount NFS export on proxmox 6

I have changed to the newest version and using ubuntu server 16 as my NAS, mounts are fine now, but did not work with Rockstor. So there are some compatibility issues.
 
Proxmox would not also mount time capsule CIFS, so go figure...... Not that i need it, but.... well.... maybe apple using CIFS 1 or something.
 
I found a work around for this issue. In my case, I just removed the NFS mounts and re-set them up for NFS v3 and they worked like a charm. There must be something with NFS v4 and our NAS that was not compatible or working correctly.
 
same here, SYNOLOGY 6.2.4, NFSv4 shared enable (also tried with NFSv3)

from LAN, Proxmox 6.3.6 => webUI, add NFS : OK
from WAN (port forwarding enable, firewall OK):
- Proxmox 5.4 => webUI, add NFS : OK
- Proxmox 6.3.6 => webUI, storage -> add NFS => wait and spin, and nothing

my workaround yet
- Mounting from CLI work like a charm so
mount -t nfs4 server:/share mountpoint
- then webUI, storage, add Directory => select mountpoint
 
same here, SYNOLOGY 6.2.4, NFSv4 shared enable (also tried with NFSv3)

from LAN, Proxmox 6.3.6 => webUI, add NFS : OK
from WAN (port forwarding enable, firewall OK):
- Proxmox 5.4 => webUI, add NFS : OK
- Proxmox 6.3.6 => webUI, storage -> add NFS => wait and spin, and nothing

my workaround yet
- Mounting from CLI work like a charm so
mount -t nfs4 server:/share mountpoint
- then webUI, storage, add Directory => select mountpoint
Proxmox 6 has some timeout issues dealing with NFS v3 or 4 on Synology which causes it to hang. Unfortunately, I have not found a fix other than using some other NFS server besides Synology.