The server.cfg file in FiveM is what sets all the values for the server when it starts. It is required to set a Licence key or your server will not start.
Getting a Licence Key
You can get a licence key for free from https://keymaster.fivem.net
- Create an account
- Click Register New Server
- Put in the Server IP
- Register Your Server (for provider, select VPS and put Smarty Hosting)
You will receive a server license key.
Adding the FiveM Key to server.cfg
Find the line that says sv_licenseKey and put your key in there like this:
Then you can start your server and it will be registered with FiveM.