All SSL VPN models being upgraded from 1.7 and previous, to 2.0 and above.
The underlying Barracuda SSL VPN database has been changed with firmware version 2.0 and during or after you may not be able to access the SSL VPN interface. When upgrading from a version prior to 2.0 the database is migrated as part of the upgrade process. If you had a large database before upgrading, then this process could take up to 20-30 minutes. The upgrade process is often a lot quicker.
If the SSL VPN service has not come back up within 30 minutes, then this may be because a service lock has failed to be removed during the upgrade. In this case, a manual reboot of the system should allow the SSL VPN service to fully start up.
Link to this page:https://campus.barracuda.com/solution/50160000000IMSIAA4