When trying to add a new alternate email address to my AppleID I get the following message after receiving and entering the verification code by email: "You cannot use this email address. Try again using a different email address." What's wrong here?
MacBook, Mac OS X (10.5.6)
I'm surprised that you were able to get as far as getting a verification code. I've see similar If I tried to use an email that had been used with another Apple ID.
I would call Apple Support. Contact Apple for help with Apple ID account security - Apple Support
What type of email address are you trying to use?
If its en email address that ends in @icloud.com, @me.com, or @mac.com, it cannot be used on a different Apple ID. As these types of email addresses are in and of themselves apple ID's or part of an existing Apple ID already.
Adding email address to AppleID
