Weird startup message

hello I own an xbox 1 x. and for the last few months its been doing this weird message on startup telling me that my TV signal has been lost and to make sure that my cable/sat is on and plugged into the back of the xbox in the port for it. The thing is. I’ve never had anything plugged into that port ever. And if i Hard shuttdown my system (power off and pull the power cord) it doesn’t do it on the initial startup right after. I have even gone as far to completely factory reset it, and that didnt help. Any suggestions? I have the tools to take it apart and put it back together, I clean it probably twice a year as people in my house smoke and i dont like the dust and residue. sadly this weird message just baffles me.