I have had a Yongnuo 600EX-RT speedlight (knock-off of Canon 600EX-RT) for some time, and recently purchased a Yongnuo YN-E3-RT wireless trigger (knock-off of Canon SN-E3-RT) to give me off-camera flash capability. The problem I'm having is with flash triggering with the speedlight set up in Group A or Group B.
If I set both the trigger and the speedlight to Group A, or if I set them both to Group B, then I don't get a triggered flash.
I have success only with: (1) both the trigger and speedlight set to Group C, or (2) the trigger set to ALL and the speedlight set to Group C.
I'm trying to determine if I am doing something wrong, or if there is a problem with the transmitter or a problem with the speedlight.
Anyone have any insights?