Signs and chat not visible

Hello! When I text in chat other players cannot see it, and when I place signs nobody can see it, not even me. I've tried everything I can think of, right down to reinstalling the game, and nothing seems to be working to fix it! I can't imagine I'm being censored, as I can't recall saying anything offensive in the text chat, because my friends and I always just call each other when we play. Any assistance would be very much appreciated.