Output no change

Good morning,

I am new with DAQmx and I use the Cont Write Dig Port-Int Clk.vi example in order to understand how it works. My board is USB-6343 OEM

I changed the example above with my configuration Port0.12 and Port0.13 (only two output). I measure these outputs with an oscilloscope.

I can switch these outputs on and off and also generate continously a square signal with MAX. The hardware is ok.

But the example does not run. There is no error and no change on the outputs.

Can any body suggest me a way to solve this problem.

Please see the picture in attachment.

Thanks in advance