I have a similar if not exactly the same issue. I try the start the app, i shows the big "Prime Video" logo and the screen goes grey (like the apps usual background). If i switch to ordinary TV or Netflix and back to Prime Video, i just get the grey screen. When i restart the tv it does the same thing again, first the logo then a grey screen.
I have a [LG] webOS TV OLED55B7D with firmware version 05.80.15. The internet connection works fine for Netflix and all other smart tv functions.
Things i tried so far:
i uninstalled and reinstalled the app -> nothing changed
i did a factory reset with the tv, reinstalled all apps etc. -> still the same error
i went the the Prime Video website and removed the tv from the devices list (in hope that this would force to establish a new binding) -> no changes either
Perhaps someone has found a solution to this...
