Two channels not working

FS1 (channel 26) and sometimes IDPAC (channel 80) doesn’t work. Acts like low signal pixelation on 80, nothing on 26. 26 says “We’re having some trouble on our end”, that being Cox. Been like that for a long time. Changed boxes, nothing. All other channels work. So interference? Can’t figure out what’s going on. If I get no ideas from the forum, I’m giving Cox an ultimatum. Fix it, or I quit them. It’s obviously a problem outside my house.