Unable to connect with S24

[Supernova4422]

Hi, I have set up the sonoff server on my raspberry pi, and have a sonoff s24 switch.

Following the guide I was able to have it connect to my home WiFi (I initially did it as a hotspot on my phone, but when I took the switch home it connected fine to my Wi-Fi). However the sonoff server doesn't seem to be detecting it on the network. /devices returns [] for instance. I'm not sure if there's a step I'm missing (such as updating the config.js) or firmware changes have made this tool obsolete.