NFS won't mount directory, where to dig next?

Question

System administration

Others, I can’t understand what is the problem:
the client cannot mount via nfs the /mnt/usb_storage directory shared on the host machine
server 192.168.1.50
client 192.168.1.35

/mnt/usb_storage - this folder must be mounted on 192.168.1.35

On the server in the file etc/ exports is written /mnt/ usb_storage
192.168.1.35(rw,sync,no_root_squash, no_subtree_check

)

~# mount 192.168.1.50:/mnt/usb_storage /root/Yandex.Disk/
mount.nfs: timeout set for Sat Dec 12 00:44:09 2020
mount.nfs: trying text-based options 'vers=4.2,addr=192.168.1.50,clientaddr=192.168.1.35'
mount.nfs: mount(2): Operation not permitted
mount.nfs: trying text-based options 'addr=192.168.1.50'
mount.nfs: prog 100003, trying vers=3, prot=6
mount.nfs: trying 192.168.1.50 prog 100003 vers 3 prot TCP port 2049
mount.nfs: prog 100005, trying vers=3, prot=17
mount.nfs: trying 192.168.1.50 prog 100005 vers 3 prot UDP port 38996
mount.nfs: mount(2): Operation not permitted
mount.nfs: Operation not permitted

The firewall is disabled, nothing interferes
With the command on the client, the server gives the host, does it mean a plug on the client?

~# showmount -e 192.168.1.50
Export list for 192.168.1.50:
/mnt/usb_storage 192.168.1.35

Where to dig next?

Server
[email protected]:~# uname -a
Linux proxmox 5.4.78-2-pve #1 SMP PVE 5.4.78-2 (Thu, 03 Dec 2020 14:26:17 +0100) x86_64 GNU/Linux

Client
uname -a
Linux servername 5.4.78-2-pve #1 SMP PVE 5.4.78-2 (Thu, 03 Dec 2020 14:26:17 +0100) x86_64 x86_64 x86_64 GNU/Linux

Answer 1

you most likely have an unprivileged container. Mounting will not work in it.