iCloud login error (me.com, mac.com, etc)
Creating a password to use with TouchMail
https://support.apple.com/en-us/HT204397
Entering your username & app specific password in TouchMail
In the Add Account screen after you enter your email address please click Optional Settings. iCloud and me.com use slightly non-standard implementations, so in the Username field enter just the account and not @icloud.com. For example for bob@icloud.com you would enter bob@icloud.com for the email address, and just bob for the username.