I bought my first flash, the Neewer Speedlite NW561, for my Canon 6d to use on and off camera. I was testing it on camera by placing it all the way in on the hot shoe but it seems like the light is not compatible with the camera. The camera still thinks there is no flash attached. I heard there is a way to connect a 3rd party flash to the camera while it is in the hot shoe and I was hoping for some guidance.
That is a very basic Manual power flash that is not compatible with the camera's flash menu. Only auto ETTL flash units are compatible, and even some of Canon's older ETTL flash units are not compatible.