I've successfully accessed the Security info of my Microsoft Outlook.com account, and I'm trying to add an alternate email address.
During the last 3 days I've tried it several times, but each time when I enter the new alternate email address, this error appears:
"There's a temporary problem with the service. Please try again. If you continue to get this message, try again later."
On my Windows 7 SP1 64-bit PC I've used both Internet Explorer and Firefox, both resulting in the same error message.