He says that there are TWO tv's the FireTV and a SmartTV. The link you provided addresses someone that has a FireTV only. The SMART TV should be able to use the antenna without issue.
Additionally, the poster says this has happened a couple of times, which would indicate that the TV has worked previously. Not sure if they mean BOTH tv's one or the other. But based on the tenor of the message, it would indicate that at one time or another, BOTH tv's were working, and to have fire stick or fire tv, it would ALSO indicate that they have internet.
SO, I stay with my original post, in that the question makes no sense. The TV's would HAVE to have been setup, they required internet to use internet functions, BUT they should be able to use an antenna without internet. I just tested both my hisense, AND my samsung, both can access antenna tv with internet down, AND the hisense has a amazon firestick 4k plugged into it.
Doesn't Amazon sell Smart TV sets built on the Fire TV OS?
It'd be beneficial if OP posted makes and models but since "Fire" is festooned throughout the post, I assume everything has the Fire TV OS. There may be a way to force into the OS...such as holding the Power button...to remove CoxWiFi as the network ID.
The link I posted reads the Fire TV (OS) needs to be activated before operation...even operating via an antenna. I agree the TV were operational beforehand, but for some reason the OS keeps losing its authentication.
Perhaps it would help if we knew the model number of the TV?
