For some weird reason got the network error(being enabled since morning irrespective of the f/b chat issue)a small workaround:toggling between the online and offline tab clears the error at least that works for me.

maybe you guys can give such a try

Having this issue on my N9 here! ..and there seem to be quite a few people on Nokia Discussions also having this problem logging onto the chat.

Stopped working for me in the few recent days. It logs in just fine (no problems reported), but nobody is shown to be online. I tried rebooting and recreating the account, to no avail.