Error refused

The server refused the connection

A machine is at that address, but nothing is listening on the port. The NFS service is probably switched off, or the app is pointed at the wrong port.

What this means

The server answered — with a TCP reset. That’s what an operating system says when nothing is listening on a port. So the address is right; the service isn’t there.

If you’re using the normal (portmapper) mode

The app first asks the portmapper on port 111. A refusal here means rpcbind isn’t running. Two very different explanations:

  1. NFS is switched off on the NAS. Every NAS ships with NFS disabled.
    • Synology: Control Panel → File Services → NFS → Enable NFS service.
    • QNAP: Control Panel → Network & File Services → Win/Mac/NFS/WebDAV → NFS Service → enable.
    • TrueNAS: System → Services → NFS → running (and Start automatically).
    • Unraid: Settings → NFS → Enable NFS: Yes.
    • Linux / Raspberry Pi: sudo apt install nfs-kernel-server and sudo systemctl enable --now nfs-server.
  2. The server is NFSv4-only and doesn’t run a portmapper. Some servers (TrueNAS with NFSv3 disabled, hardened Linux boxes, some Docker images) only speak NFSv4 on port 2049 and never start rpcbind. In NFS Files, open the server’s Advanced settings, set NFS Version → NFSv4, turn on Custom Port and enter 2049. The app then skips the portmapper entirely.

If you’re using Custom Port

Then the port you typed is closed. Check the server’s configuration for the port it actually uses. Userspace servers commonly use 2049 or a high port like 20490; check their log line on startup.

A firewall can also “refuse”

Most firewalls silently drop (which gives a timeout), but some are configured to reject, which looks like this. If the NAS firewall is on, add a rule allowing 111 and 2049 (and mountd) from your subnet.