# ⚠️Error: Could not authenticate server license key. Invalid key format

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This issue is caused by an `Invalid Authentication Key`, you can fix this by heading over to [keymaster](https://keymaster.fivem.net/) and getting a **free key** for your server.

When you have got a key, head over to the `Settings` page on your server, and paste the key into the `fivem license` box.

Click `Update` and then restart your server,

***In some cases you may need to click `Reinstall`***