Have you tried at least to unplug the cable-company wire from the cable-box, and plug it back in?
That is probably actually a twist-off/on co-ax cable. To take that off you’d unscrew the big nut at the end from the connector on the box, then pull the cable out.
To clean the connection of oxides work the center wire into the connector and back out a couple times.
Then center the middle wire into the connector, snug it up then screw it back on.
If that is a short cable to the incoming wire do the same thing at the other end of that cable.
Maybe you did that already…