Which unholy act do I need to perform to login?

I can log in to the main portal, ie https://manage.windowsazure.com/[etc].

From here I can add/delete users, servers, and DBs etc. Awesome. Magic.

When I click on manage server or DB, though, it opens a new tab (https://[servername].database.windows.net)

I enter the same credentials that got me into the main website. No luck. Login failed.  

I've tried a bunch of other combos, e.g. username@servername,. No luck. Login failed.

I've tried connecting through SSMS. No luck. Login failed.

Which voodoo magic am I forgetting to invoke?