This is stupid. The server evidently recognizes my login details.
If I use another email address than the one I registered my Spore account with, it says "Invalid login" right away. However, if I use the correct email address, it says "Connecting to the Spore server", then tells me it'll connect my installation to that Spore account. THEN it says "Invalid login"!
Is this what I paid good money for? I even got the Galactic Edition!