Live Mail not recognising my password suddenly.

Suddenly I cannot access my email accounts.  It won't take my usual password.  I tried right clicking on my left hand side email account name as I read that others are struggling with this issue but the password box is greyed out.  I can only make it work if I check the box for "password authentication" (whatever that means) and I change the password and it still won't work.

Someone please help.  I need to be in critical touch with my family and have not been sending or receiving email for over a week.  I have Windows 8.1  It seems that all this happened suddenly after my computer ran some updates.  I have seen several discussions referring to incompatiblity now with POP accounts.