troubleshooting - My Godox flash won't fire off-camera. What should I check?

I have a Godox flash with a built-in radio trigger, and I honestly can't figure out what I'm doing wrong. I've checked that:

• All the batteries in everything are good and everything's turned on.


• The radio transmitter is seated fully forward into the camera hotshoe and that all the pins on the flash foot are meeting the contacts in the camera hotshoe.


• Both the transmitter and flash use the same channel.



• The flash is in slave mode.

But the flash isn't firing when I push the shutter button. What else should I check?