You’ve basically got two separate things happening in that log:
openclaw gateway restartis trying to talk to a supervised service (systemd user unit on Linux), but your shell session has no systemd user bus:
systemctl --user unavailable: Failed to connect to bus: No medium found
That usually means you’re on a VPS/minimal login where systemctl --user can’t connect (common over SSH unless lingering/user sessions are set up).
- Independently, the Gateway process is already running and holding the port:
gateway already running (pid 1287387)
Port 18789 is already in use
So “restart” can’t work (no systemd user bus), and “start” can’t work (port is taken).