Receive only no transmitt

I have a Icom 703+ all the correct cables and I am trying to use Fldigi. I have read all posts here pertaining to 703 and even talked with Denis from Digirig. He checked my strings and all looked fine . I am at my Witt’s end, so if anyone can help please let me know

Does the radio key up when you simulate the PTT by shorting the contacts on the Digirig’s end of the cable as shown in this video?