@Christophe,
In addition to being able to access a .lic file from the link above, when you downloaded the latest license server installation materials, that .zip archive also contains the same .lic license file.
On the license server, nothing in the license file should be changed, other than the 2 port numbers if you wish to choose custom ports.
Using a license file to license a multi-user client PC, for the copy of the license file on the multi-user client PC you would modify the port numbers to match any custom ports you specified in the license server's license file, and you would change "this_host" to be the license server's address.
Often, we see people try to add feature blocks or make other changes to the license file beyond those described above. These are not necessary for FlexSim's licensing configuration and can result in your licensing failing to work properly.