one week chat works fine, the next I`m having connection issues

As the title reads, I can't connect to chat. It appears that I download the chat software, but my computer fails to connect. It says connection failed. I have the most update software on my Macbook. I tried downloading the latest adobe flash player, still no luck. Is this a matter of me being banned? I don't see why I would have.

I'd like to see some of my regular friends again, please help.