I was using my SB-700 as usual: in remote mode on TTL with my D610. Always works no problems. Halfway through taking pictures, the flash stopped firing. At first I thought the batteries ran out, replaced those, but still is not firing in this setting. Camera and speedlight are set up properly/have the correct settings on for it to work. It just will no longer fire the flash in this specific setting. Yes, the on camera flash was up. Camera was in correct commander mode with corresponding speedlight settings. The SB-700 still turns on and functions in other ways, for example will work in manual when settings are selected from the camera in remote mode. The speedlight also works appropriately when mounted on the hot shoe. I can just no longer get it to work specifically in remote on TTL. What am I doing wrong, what happened?? All suggestions welcome!