Error unsupported

The server doesn't support something the app needs

The server answered, but lacks an operation NFS Files relies on. Try pinning the other NFS version; if that doesn't help, email the message.

What this means

NFS Files asked for an operation the server says it doesn’t implement. Full servers (Linux nfsd, every major NAS) implement everything the app uses; the ones that don’t are usually small userspace servers.

Try

1. In the server’s Advanced settings, set NFS Version explicitly — NFSv3 if it was Auto or v4, NFSv4 if it was v3. The two versions have different required operations.
2. If the server is a Docker image or a small Go/Rust/Python NFS server, check for an updated version; several gained missing operations recently.
3. Email the exact message from the alert (Settings → Contact Support fills it in). Knowing which operation and which server lets me either work around it or document it here.