Help and Support for CleanEmail
Clean Email currently supports all email providers. For Gmail (including Google Apps/Suite), Yahoo! Mail, Hotmail, Outlook, and Office 365 you do not need to enter your password. For other providers like FastMail, AOL, iCloud and other IMAP-based mailboxes you will need to enter your email and password to connect an account.
If you have a two factor authentication enabled, you may have to generate an app specific password to use with Clean Email. Also, for custom email servers/ IMAP based mailboxes you will also need to enter the IMAP server address. This is usually provided by the email service in their documentation.