We have just fixed the bug that your web Facebook Chat does not receive messages from your friends in the recent days. Now continue to enjoy chatting with friends on Facebook Chat.
Thanks @bartu for reporting this problem.
BTW: Recently some users reported that Facebook asked them to verify and confirm their accounts’ security and recent activities. We had explained it in blog post “Tips on Logging into Facebook Chat” some days ago. We recommend you reading it if it happens on you in the future.