I just replied to your PM. Reply here or directly to me if you're still having issues.
Are you running a firewall? Muse needs to be able to make an http connection to Adobe's servers. Firewalls usually allow this, but it's possible your firewall is set up to block certain http connections. Please try turning off any firewall running on the machine and see if that resolves the error.
There's nothing apparently wrong with your account, Amy.
Are you able to log into the account using the same e-mail address and password on Adobe.com?
To check, go here: http://adobe.com/go/membership
If you can, then I expect that Abhishek's suggestion of checking for firewalls or other security software to be the best thing you can do. Likely, something on your computer is preventing Muse from connecting to the Adobe servers.