Update my situation:
Things I have done until now.
1. Uninstall vocalizer driver and delete everything from %appdata%.
2. Download the driver and reinstall it.
3. At the activation, I get the following error.
"Error verifying credentials: Can not connect to Vocalizer for NVDA server. Please check if your internet connection is working."
4. I already contact IT department in my workplace regarding both errors. They don't know the address, IP or something like that of the Vocalizer for NVDA server, so they cannot do anything for now.
5. I sent an e-mail to Tiflotecnia regarding the problem.
What should I do next?