I have a new Godox speedlight, and I can't get it to trigger from the hotshoe of a D5600. It seems to work fine with a wireless flash trigger, though.
When I have it in the hot shoe, in iTTL mode, with auto zoom, and the camera in Aperture priority, it seems to think the camera is at F1 (it isn't), and doesn't seem to read the zoom. I get low light indicator in the viewfinder, and no flash. Hitting the flash button pops up the built in.
Do I have a defective unit? Any tests to do?
To reply to some of the comments, and give current staus: The hot shoe works "properly" with some other flash units-- the godox X1 transmitter, and a Zenith ring flash -- with "works" meaning "triggers a flash". That said, I'm not sure how to get confirmation that TTL is working at all. I wouldn't expect it to with the Zenith, and would with the transmitter -- but I don't know how to verify this with the X1, as the TTL numbers don't come up on the screen.
I moved the flash around on the shoe until it felt like the pin dropped in and I could no longer move it. No change.
I read somewhere that shorting the big center pin to the plate on the flash should trigger a flash. It does not. Is this a real test?