Help please with firewall UniFi problem

I have a Default Network (VLAN 1) and IoT Network (VLAN 2) The 2.4 GHz band is IoT exclusive.
The problem is that I cannot access (ping) the IOT Net from DEF Net. Not a problem with wired devices which dont have a web user interface, but want to add additional wired IoT devices which have web and app interface. Curiously, the only one wifi device on 2.4 GHz (IOT Net) is communicating to his iPhone app.
In zone firewall II created an Internal to Internal rule - Block IOT to DEF with Return Traffic allowed.
Below this is the Isolated Networks whic I think causes the problems but this cannot be edited.
Help please

I would put IOT in the DMZ. I have a full tutorial on how the Zone Firewall Rules work here: