Unable to sync icloud mail with Windows 10 mail app

I had this problem too, but the app-specific password generator did the trick for me.

As my iCloud email is protected with Apple's two step verification, I needed an 'app-specific password' to sign into an app that's not provided by Apple, like Windows Mail which doesn't support entering verification codes.

Here's the steps (done via my laptop):

• sign into Apple ID with your iCloud email and password: https://appleid.apple.com/account/manage
• if you're a two step verification user, your device (for me, my iPhone) will give you a verification code to enter after you put in your iCloud email password
• in the 'Security' section, hit 'Edit'
• in the 'App-Specific Passwords' section, hit 'Generate Password...'
• enter a label for this password (I typed 'Windows 10 mail app')
• hit 'Create'
• an app-specific password will be created for you, in this format (case sensitive) tmah-jdbq-rdyy-gdes
• copy the password and hit 'Done'
• now open up Windows Mail > settings (cog icon) > manage accounts > select your iCloud account and enter your app-specific password then 'Save'

Your iCloud email should now start to appear. Despite spending days looking at the config settings, it seems Windows Mail pre-set config is correct, so you shouldn't need to change the incoming or outgoing email server settings:

Incoming email server: imap.mail.me.com:993:1

Outgoing (SMTP) email server: smtp.mail.me.com:587:1

I hope this helps someone. A word of warning though. If you change your primary Apple ID password, all your app-specific passwords will be automatically revoked and you'll need to generate a new one for any apps you want to keep using.