Set up a custom domain for a potential business through Cloudfare registrar. Linked said domain to my personal iCloud account. As business took off, emails became more difficult to organize and I needed visibility of ONLY the business emails, so I created a separate iCloud account for the business, gave domain permissions to the new iCloud account. Reverted former account back to original email as primary; however, the custom email that I created is still shown as "default email" under the personal iCloud account. I'm unable to link this custom email to the business iCloud account, as it says already in use. Cannot figure out how to remove it from "default email" under the former iCloud account- any help is appreciated. Have already been on the phone with apple... no solution there.