I think it was 318, at least. I just remember that the gist was, "You've reached the message rate limit, please avoid spamming." I have no idea what the rate limit even is, but that's a moot point because I had posted in chat a grand total of 0 times in the hour or so I was just playing. I was able to log back in without issue, it seems (which is nice, considering the game crashes when attempting login about 25% of the time, these days, but that's a different issue).