@larry.h, if you didn’t change the “network mode” on the Mango (“More Settings → Network Mode”), then it is in the default “router mode,” so it is likely behaving similar to your home router/firewall/access-point device: anything on its network is “secure” and anything elsewhere is “insecure.” (I use these terms loosely.) Think of the Mango as your home router/firewall/AP: anything in your home network is safe, but anything outside your home, trying to get in, is blocked. So, the Mango is “protecting” your home network devices from getting to the devices the Mango has let onto its network.
Think of it like a nested set of protected networks: your home network is protecting your home devices on the Legoland network from the nasties on the Internet, and now additionally the Mango is protecting the IoTaWatt from the devices on your Legoland network.
I changed the network mode on my Mango to “Access Point” so that it acts only an a wireless access point (WAP) on my network, i.e., it does no routing or firewalling. (I have mine hard-wired with a CAT6 cable.) In this mode the Mango becomes just another client on your home network (you can have it pick up a dynamic or static IP address from your home router’s DHCP server), and then wireless devices that connect to the Mango SSID (i.e., the IotaWatt) will also get their IP addresses from your home router’s DHCP server. At that point, everything should be in your same home network and you should be able to access the IotaWatt from your phone or laptop in your home network “Legoland.”
Cross reference other thread here: Remote mounting IoTaWatt from electric panel - #11 by larry.h
Network mode on GL-iNET devices: More Settings - GL.iNet Docs