We've been honored to host & give you a great way to view your iCloud, @mac and @me accounts, but we're sad to say that Alto is no longer able to support them as of December 2, 2013.
We sincerely regret the frustration this change will cause.
You can simply wait and do nothing and you will automatically lose access to your iCloud account(s) on December 2nd.
Or, you can close your account now by clicking the Plus sign (+) on the left of your Alto inbox, then clicking the iCloud account name and the Close Alto Account button (if it's your main account) or Remove Account button (if it's an added account) at the bottom of the column that opens.
We continue to be dedicated to offering you a great view of your non-iCloud email accounts. Any other supported IMAP-accessible email will continue to work, including Gmail, Yahoo! Mail, AOL Mail and others.
If this is your main account in Alto, and you already added other accounts to this one, you can sign into Alto with one of those other accounts and re-add the other(s) to it. Unfortunately any stacks you might have created will have to be rebuilt.
Again - we are very sorry for this inconvenience!