By default, Satisfactory servers will pause the game when there are no players connected. This means that conveyer belts will pause, and all resource production will always pause. If you would rather have it so that these continue while players are offline so you can come back to plenty of resources, you can use these simple in game steps to disable autopause.
1. Open the Server Manager
2. Click your server, then click Server Settings
3. Toggle the setting for Auto Pause to your liking.
4. Click Apply. You can now toggle your server to let production continue while you're offline.