iCloud mail accounts

I have Outlook for Mac and I'm trying to attach my email XXXXXXX@icloud.com as a mail account to Outlook. When asked to insert my password it keeps saying "wrong password". A long time ago I recall setting up an iCloud account myname@icloud.com on a Sony laptop. Years later I switched to Mac, bought a MS suite of apps including Outlook. I'd like to add myname@icloud.com as an Outlook mail account. However, the password for my Apple ID keeps getting rejected. Is this because of a problem with Outlook?