Hi @pixelboy
When the core powers up and is put into flashing blue listening mode, it is listening for a special WiFi packet that tells it the SSID and password, which are sent encrypted. The core does not have any bluetooth connections; it all happens over WiFi even though the core does not have the SSID and password yet. It is really quite clever.
So the phone or device with the app needs to be on the network you intend to connect the core to.
The technical details can be found here: