Registering with Outlook accounts won't work

[Spack]

Currently registering with any Outlook email address, which includes Outlook.com, Hotmail.com, Live.com, country variations, and any other domains hosted by Microsoft, will not work because the email to confirm the registration cannot be delivered due to another server on the hosted network range being blocked from sending email. The hosting provider is trying to get this block removed, but until then please use an alternate email service for registering here. 

Dan