Nikon D600 commander mode not working?

My Nikon D600 commander mode will not trigger my SB700s. The built in flash is going off but it won't trigger the external flashes for some reason. The D600 is in commander mode and the SB700s are in remote. All on channel one and group A.

Any idea why it's not working?

All of your answers are in the manual.

Make sure that they'll all set to the same channel.

Be sure the sensor on the camera can see the on-board flash. For experimentation purposes, aim the SB700 sensor at the flash of the D600.

Otherwise, find a helpful video on YouTube or web page which will tell you exactly how to set up the system. Sometimes the manual seems like it was written by a UNIX guru - information is there, hard to comprehend.