Denon AVR-1910 support X1 cable box

Hi Support,

I use Denon AVR-1910 connect TV box as input and connect projector as output. it worked before X1 TV box. my TV projector support coaxial cable. I install the new box which supports X1, I only have no color video. I also try use HDMI as input. it did not work either (no video). What is my next step on trouble shooting.

Thanks