How exactly are you configuring the wifi for the Zero?
AFAIK it cannot be done on a emonSD image without using another Pi with Ethernet or possibly with a micro-usb Ethernet adapter.
The official Pi way of doing it is to add a wpa_supplicant file to the boot partition on another PC before inserting the SD in the Pi zero and booting, the Pi Zero then finds the file on the boot partition and configures the wifi during setup. The emonSD is read-only at boot up and that wifi configuration facility doesn’t work.
see the Using wpa_supplicant.conf file on the emonSD boot partition thread and possibly the Raspberry Pi Zero W SD image thread too.