When you can't spin pokestops or catch pokemon, it is most likely a soft ban that occurs when you login at two un-humanlike distances within a short period of time. I've encountered this at least 20 times, each of them lasting at least an hour, sometimes a few minutes over each hour. Those often result in an hour-long IP ban as well, meaning any accounts logged in from the same network will be unable to view any pokestops, find any pokemons or see any gyms.