One of the things I find that sometimes helps is if you log out of the forums, quit out of your browser completely and restart it, then log back into the forums and chat.
The chat software we use is no longer actively developed. This is a problem we keep coming across time and time again with these chat platforms -- the developers walk away from the project or service. We can always move to another one, but we know how much members hate changes like that. And we find that virtually every chat platform has its share of glitches for some members.