I found this in the documentation:
„If you are using a Commercial Edition of Zentyal, you could access to the Antivirus left menu, and then, you can enable virus analysis for your shared files. You can also add exceptions for the folders that do not need require virus check. You need the Antivirus module installed and enabled to use this feature. The check is done in real time when trying to access a file, resulting in an access denied error if the file is infected.”
I understand why disappeared...
I found the SOGo menu under Mail...