I have a VU+ Duo2, that is replacing a DB8000, it is connected on a 1G switch to a network IPv4. Gets it IP setting from a DHCP. This all works fine. Even the web server works. But when I run the network test I get a error on the IP address. Even when I switch to a other manual IP address. I don't see any activity on my firewall, or on my switches that would indicate a problem. Hens there must be a problem with the VU+ box, hardware or software.
But were best to start looking?