Digital box not getting signal

I have talked with Telus and Roku three times. I have tried three digital boxes. What am I doing wrong?

I am connecting a Telus digital box to my Hisense Roku TV. I have selected input HDMI 1 and plugged HDMI cord into that input on TV (I have tried all three inputs).. When I try to watch cable TV it keeps telling me it is searching for a signal. I have tried the box on a 2nd TV as well with no luck.

It worked originally when I first added cable TV. Any ideas? Telus nor Roku seem to be able to solve the problem.

Any suggestions before I call Telus again?

Sue