Fix txAdmin E5800: port 40120 already in use

FATAL ERROR: E5800 means txAdmin could not start its HTTP listener because the selected port is already occupied. This is separate from the FXServer game endpoint, commonly port 30120.

1. Identify the processCopy Anchor Link

On Linux:

sudo ss -ltnp '( sport = :40120 )'

On Windows (Command Prompt):

netstat -ano | findstr :40120
tasklist /FI "PID eq 1234"

Replace 1234 with the PID reported by netstat. If you customized TXHOST_TXA_PORT, use that port instead.

Do not kill a PID unless you have confirmed its identity and operational impact. It may be another FiveM server or an unrelated service.

2. Choose a safe resolutionCopy Anchor Link

• If a duplicate FXServer is running: stop the duplicate cleanly using your service manager or host panel.
• If hosting multiple servers: allocate distinct panel and game ports and separate txData directories.
• If another service owns the port: use a permitted unused panel port and update firewall, container mapping and proxy configuration together.

For txAdmin v8+, set the panel port before starting FXServer:

export TXHOST_TXA_PORT=40125
./run.sh

Or in a Windows batch launcher, set TXHOST_TXA_PORT before starting the appropriate server executable. Changing server.cfg does not change the txAdmin HTTP listener.

3. Verify both listenersCopy Anchor Link

1. Restart the intended FXServer process.
2. Confirm the E5800 message is gone and the startup log prints the expected txAdmin URL/PIN flow.
3. Open the panel through the newly assigned port.
4. Start the game from txAdmin and test a player connection.
5. Confirm no second instance shares txData or either port.

If the listener starts but the panel is not accessible externally, follow Panel not reachable. For a container, use Docker networking or Pterodactyl port allocations.

Sources: E5800 upstream report, current host variables.