In order to add an Apple based email address you will need to create a special password for Spamdrain in order to allow our servers to access your mail.
If you have two factor authentication disabled, please enable it and create a special password for Spamdrain to log in. Newly created password should be entered in the password field at your Spamdrain's settings page. Just click on the added email address, update the settings with new password and click on Save.
App specific passwords allow you to sign in to your account securely when you use Spamdrain. In order to get the password, please refer to the following step by step guide from Apple:
https://support.apple.com/en-us/HT204397
Keywords: me.com, apple, icloud, two factor authentication.