BT Whole Home network drop out if no internet connection
I have the BT Whole Home setup (White discs). I have 3 Discs all hard-wired to Network Switches around the house, which intern are hard-wired to a Home Hub 5 (with WiFi disabled). Whenever my broadband drops out I lose complete network, meaning I can't access any of my servers or other computers or devices.
I can still get assess to my servers with the hard-wired computers just not the ones connected to the BT Whole Home WiFi like my Laptop.
What would cause the whole WiFi network to drop out just because I have no broadband?