Confusing...it worked at the first site, so maybe there's a chance that the problem is with the cable feed at the other sites(?) Campground cable TV in our experience, is not great...so that's usually the cause.
But it is best to check everything first.
IMHO, The easiest way to check campground cable TV at any individual site is to run a coax directly from the post to a TV's RF input...bypass the RV's distribution system...then program search for channels...and you will know what is on the coax as a baseline.
First and always, signal amp must be off for cable TV
Second, check that your coax for the post to the RV connection is intact...no chaffed insulation, and the end connectors are tight to the wire/shield on each end. A lose end connection will give the described issues.
And just to check...here's the factory videos on the topic:
And
Best luck