mail server password not working

when sending an email from my Windows 7 pc via my iCloud account via Outlook 2010 I keep getting a pop up window that says:

"Enter you ruser name and password for the following server."

"Server p09-smtp.mail.com"

"User name (autofilled with my prefix to my iCloud.com email address, but I can change it)"

"Password (autofilled completely with asterisks **)"

I've tried entering my iCloud login password, my Apple ID password, my Microsoft password all while leaving the autofilled user name. Nothing worked. Then I tried changing my username to my iCloud user name, my Apple ID, my Microsoft username (which are all the same email address), with the corresponding passwords. Nothing works!

Help!!!!