Emailing from the iCloud
Can you now email from iCloud.com? Did you check to see if your me.com and mac.com email addresses got its third evolution of @icloud.com?
Log into Mail at www.icloud.com. Click on the gear icon in the upper right corner of Mail. Select Preferences then go to Accounts. In the middle of the Accounts screen, do you see something like this?
If you see an address with icloud.com, you’re all set. Send a test email to your account @icloud.com to verify it’s working.