Facebook chat not workin

Question

my facebook chat was previously working fine but for the last few weeks everytime i try to go onto to it a pop up comes up saying:

transport error (#1001) while retrieving data from endpoint
'/ajax/chat/settings.php?_ecdc=false': a network error has occured. please check that you are connected to the internet.

how it can say that im not sure as im obviously connected to the internet as wouldnt be on facebook otherwise. the rest of my facebook is working fine. does anyone know how to solve this very annoying problem?????