If you're seeing "error contacting server" messages, please take a look at this feedback:
You may get "error contacting server" when you start Foldit, or when you try to upload or download a solution. Usually, it's just temporary, and the problem clears up within a few minutes. It seems like some players are seeing the problem more consistently. Some additional information may help the development team track down the cause.
Please add to the feedback if you're having network-related problems with the game. If nothing else, it will help the Foldit development team understand how widespread the issue is.