The F connectors often fail over time, either vibrate loose or corrode. Recommend you take the wall plates off, inspect, clean and WD40 every connector you can reach. On my rig, the antenna connection on the roof corrodes. The connector inside behind the booster near the ceiling vibrates loose.
Then check continuity on each section of coax - in the process learning where each section goes.
While the plates are off, notice whether the internal coax used was RG-6 or the smaller RG-59 which may not carry the cable signal.