When you start a station with no license or even a bad license, the driver will run in demo mode for 2 hours allowing full functionality. Once the time expires, the driver stops working and you need to restart the station to begin demo mode for another two hours or allow a new license key to take effect. You were likely running in demo mode when you had the devices up.
Zero device license are not sold but the license key generation is based on product codes provided. You will want to refer back to the distributor you purchases this from and supply a proper product key that matches the amount of devices you purchased form them for the license key to be generated accurately.
You will want to license for all of the devices you purchased regardless of what you expect to use So if you purchased 100 devices, you will want to license all 100 for this installation since you can’t break those devices into multiple installations.