I had 61k iron to go to upgrade to stronghold 12 (489k needed) 428k iron. Suddenly the alliance chat disappeared except for system messages. I logged out and came back in and it was corrected. But I only had 237k iron! I had 237 gems, too - coincidence or part of the bug?
That doesn’t sound like the general result of what happened with chat. Have you opened a help ticket? If not, I’d make that my next stop.
It’s look like a problem with connection. You should create case in support https://support.smallgiantgames.com