off camera flash ???

Im using radio triggers to fire my yongnuo yn560-II . . When shooting Im getting a ? mark warning say not enough light recommend using flash. Im shooting in manual model. Light meter inside camera says it to dark. But the pictures turn out good. Can someone explain what Im doing wrong ?I got the camera set for TTL . if that matters.

The camera setting for TTL only applies to the internal flash, only when that flash door is open and the internal flash is in play. Otherwise (if flash door is shut), it simply does not matter what it says. The camera menu does not apply to a hot shoe flash or to a remote flash (only the internal flash, when it is in use).

You are not doing anything wrong. System flashes like on the hot shoe are recognized as being present and ready (and the camera can interact with them in some ways). But the remote flash on the radio trigger is not recognized as being present (not part of the Nikon system, so to speak), so the camera naturally may fuss about insufficient light (it is insufficient, and you do need flash). The flash should take care of it (i.e., your results are good). It is not a problem. It is too dark, and you do need more light, but the flash is handling it.

Thanks WayneF for clearing that up for me Good light to you !