Finally, another workmate could contact with Flexera support on Uk (+44 (0) 870 873 6301) and they sent instructions about activation. I share this with you.
1. Close the product and the activation wizard
2. Delete any file(s) with MVSN in the filename at the following location (you will need to enable hidden files and folders to see the .data and .001 files):
On XP or older: C:\Documents and Settings\All Users\Application Data\FLEXnet On Vista or newer: C:\ProgramData\FLEXnet
3. Set the following registry key
4. Re-launch InstallShield 2014 and if prompted, activate (xxxx-xxxx-xxxx-xxxx)
In my case, this solution are valid and now still working again!
PS: It is very frustrating that an IT company not response a support questions by email and finally we have to call by phone...
Thanks for all.
I just saw you solution, after submitting a new Case for the same issue using InstallShield 2019, in my case I just had to delete the MVSN, .data and .001 files from c:\ProgramData\Flexnet. I restarted Installshield and it is now activated. Thanks for posting.