Unable to mount NFS on Qnap

There is a ESXi Server 6.7 (free) and a QNap TS-212P with a shared folder and NFS protocol.

I need to mount this as a new Datastore for the backup.

From a Ubuntu VM I am able to mount the folder, but not from ESXi Web Client.

Also I unable to ping the NAS, the phisical NICs IP address, the router, Google, ...

I tried both the ping and vmkping commands (always 100% packet loss).

Thanks in advance.