Chat sometimes not working

As of today, I'm not getting a large part of the chat messages which were sent by other people.
In the first login today, I only got messages by one person and the rest appeared to be AFK. Then when that person responded to someone entering with "yes" I asked on the board if something was going on with the chat and everyone confirmed there had been (public) conversations going on. When I re-entered, it appeared to be working for a while but when everything was silent for some time, there were suddenly responses which came out of nothing... So the chat sometimes works and sometimes I just don't receive any messages (while the drawing board appears to be working normally all the time)