Change your DNS.
This happened to me a few times. I don't know the exact issue that caused it, but what I do know is that it has to do with your connection. I've gotten the same "Disconnected from server" message a few times when I used wifi, but it worked fine when I used 4G. The only way to resolve it is by waiting. If I were you, I would contact my internet provider if it becomes a common issue though.