Fixing port conflicts

bind: address already in use or Only one usage of each socket address in the logs means another program holds the port. Two ways out: change the port, or find the occupier.

Option 1: change the port (fastest)

  1. Open Settings and find “Mixed Port”.
  2. Change it to something uncommon, like 7899 or 17890.
  3. Save — the core restarts and the problem is gone. Update any programs where you had entered the old port manually.

Option 2: find the occupier

  1. Windows: in an administrator terminal, run netstat -ano | findstr 7897, note the PID in the last column, then tasklist | findstr to see the program name.
  2. macOS / Linux: lsof -i :7897 shows the occupying process directly.
  3. The usual suspects are another proxy client or a leftover core process from a previous run — end it and start again.