@Maarten Euben, since it appears that your company's use-case involves almost daily activations/returns, you may want to look into using this module shared by one of our users.
You can use it to automatically activate a license when FlexSim is opened, and return that license when FlexSim is closed.
As long as the PC is connected to the internet on start and close of FlexSim, and as long as FlexSim closes normally (doesn't crash), and as long as your users are in the habit of closing FlexSim regularly (as opposed to keeping it open in the background all the time), then this module could help you ensure that a license is available, if its not currently in use by a colleague.
Please ask any new questions regarding this module or its usage in a new question, as any such questions would not pertain to the main topic of this thread (activation/return history).