Your RFM card is most likely in the WRONG place. It depends on which is “left”.
Depending on whether it is an old or new module, it goes either part-way along or right at the corner furthest from the Ethernet socket.
The original:
https://docs.openenergymonitor.org/emonbase/rfm69-pi.html
The new:
https://docs.openenergymonitor.org/emonbase/index.html
To reset your WiFi, my crib notes say:
Reset / reconnect emonPi to a different network: To force an EmonPi back into AP mode, go into ‘WiFi’ from settings and deselect the currently selected WLAN. Click on save and then refresh. You will still have access to the emoncms instance. Navigate to the admin menu and click reboot. The EmonPi will now come up in AP mode (as no network is configured).
Force the Emonpi to AP-mode - #4 by borpin