# FiveM Server Won't Start – FXServer, License Key & Logs

FiveM server won't start or crashes immediately? License key, artifacts, txAdmin, port 30120 & server.cfg – step-by-step troubleshooting.

**Quick answer:** Read the **FXServer console** or txAdmin logs first. Top 3 causes: missing/wrong **license key**, wrong **artifact version**, **port 30120** blocked.

**If you landed here:** FXServer crashes on start, hangs at "Authenticating server license key" or players see "Connection failed".

## Error → cause → fix

Symptom / logCauseFix

Could not authenticate license keyMissing/wrong key/IP changedCreate key at keymaster.fivem.net → server.cfg

Server crashed – artifactOutdated artifactsLoad latest recommended artifacts in txAdmin

Failed to bind to portPort 30120 in useKill old process or change port in cfg

Connection failed (client)Firewall / port30120 TCP+UDP → [Firewall](/en/root-v-server/firewall-ports)

Database connection errorMySQL/MariaDB wrong[Connect database](/en/gameserver/fivem/setup-basics/connect-database)

## Related

- [Install FiveM server](/en/gameserver/fivem/installation)
- [FiveM server lagging](/en/gameserver/fivem/server-laggt)
- [Prevent crashes](/en/gameserver/fivem/protecting-your-server-from-crashes)