Chat will not load while in yahoo mail. messenger works fine?

chat will no longer load when i'm using yahoo mail. when i sign in, "loading chat" appears beside my screen name...shortly thereafter, it changes to "offline". yahoo techs haven't helped much...i went through all the steps they advised me to try...nothing works. yahoo IM feature works fine. is there a way to delete yahoo mail, re-install, and see if that helps?