@Dylan > Lets ensure you have everything set up correctly.
1) You have the cables connected to the TRS output on the FastTrackPro.
2) You have each cable running to the TRS input on the back of each speaker.
3) You have selected Input source '4' on the speakers using the attached controller.
I strongly suspect you may have missed step 3.
Further troubleshooting, are you sure there is a signal going to the FTP?