This question might be considered duplicate of this: Unable to use heroku gem cli after password changes, but it is not.
In my case I have the latest Mac OS X 10.8.3 and I've installed brand new Heroku tool belt. First thing I've tried is to authenticate by issuing this:
heroku login
I was asked for my Heroku credentials, which I've entered (many-many times), but I got "Authentication Failed" message.
I've tried signing in with my credentials to Heroku website multiple times from different browsers - it all works, but I can't authenticate with Heroku CLI.

I don't have ~/.netrc file, I don't have any fancy firewall software on my Mac. What am I possibly doing wrong?
Thanks, Alex.
Update 03/18/2013 9 PM Mountain:
This is the Heroku issue and they are looking into it:
