Connecting to a server on your local network — a Raspberry Pi, a NAS, anything at a .local address — could fail on macOS 15 and later with "No route to host".
macOS blocks an app's access to devices on your local network until you allow it, and it reports the block as an ordinary network error, so nothing pointed at the real cause. ssh from Terminal kept working because Terminal is exempt. Serverus now tells macOS why it needs local network access, and when a connection fails this way, the error tells you where to allow it: System Settings → Privacy & Security → Local Network → Serverus. If you already saw this error, turn Serverus on there and connect again.