Everyone "is not available to chat."

Last 10 games I played, I would say "gg" at the end, and every time, before the player quits/time runs out, the response is "xx is not available to chat."

Did I get chat-banned?
I say "gg" at the end of every game, win or lose. 
There are no notifications or messages saying I've been muted.

I don't think it has anything to do with your account. It also happens to me, but only with some players (the most strange is that they send me messages, but I can't reply to them). From what I understood, it might be members who chose to refuse chat (you can do it in your settings) but in this case, they are more than a few months before.

This is a glitch that has been happening to me too. It happens while I'm playing friends and they are able to read my messages and respond. You're not chatbanned, it's an issue on the sites end.

Not a glitch it's a setting you can say only friends can chat with you In game, anyone can chat with you or no one can chat with you

It could be that they are already closed out of the window and on to the next game.

It is some kind of glitch because it happens to me when messaging users in my friends list who don't have these setting activated.

Looks like they've made some changes to the UI, now chat is the second window after starting a game. But I will say, more people are available to chat from when I made this post. There is still an increase in unavailable chatters but I think it could of been from the same update and the setting to only accept chats from 'friends' or 'no one' has become a pre-selected setting.

gg everyone that commented!

"before the player quits/time runs out"
Helps to read the original post (:

I think it has to do with the Focus Mode. If you are using it, chat is not visible, so probably the opponent is shown that you're unavailable