I've played a lot recently and this is the first time I haven't been able to connect, it had been working on Monday. I am using an Xfinity router. I'm getting this exact error message.
A different issue I've had in the past is that I would have a similar difficulty connecting to the servers after being connected and then getting dropped due to inactivity (alt-tabbing while someone else took their turn). The error message was a bit different, I think it said 'unknown' something. This issue would fix itself if I attempted to connect several times or rebooted the client, so it wasn't anything more than mildly annoying.
A different issue I've had in the past is that I would have a similar difficulty connecting to the servers after being connected and then getting dropped due to inactivity (alt-tabbing while someone else took their turn). The error message was a bit different, I think it said 'unknown' something. This issue would fix itself if I attempted to connect several times or rebooted the client, so it wasn't anything more than mildly annoying.