Hello-o..? I just posted a message here to those of you who may be having trouble signing in. My post showed up but now I don't see it anymore. So I'll send it again - which will no doubt make the first post re-appear.
Anyway what I said was: Try using the beta version for signing in. Strange as it may seem that was what finally worked for me today.
(Just write beta instead of www in the address field.)