How to set up custom domain iCloud email with Thunderbird

Hello,

Yes, I have already set up my custom domain with iCloud. I was trying to get it to work with Thunderbird. Here's what I did to make it work, in case anyone comes across this thread in the future:

• Generate an app password using my iCloud account.
• Enter my iCloud custom domain email and the app password in the Thunderbird account setup. It will attempt to detect the correct server settings automatically. These are all correct except the username fields. Here are the correct settings:

Incoming server:

Protocol: IMAP

Hostname: imap.mail.me.com

Port: 993

Connection security: SSL/TLS

Authentication method: Normal password

Username: the first part of your original iCloud email address. Note that this is NOT your custom domain iCloud email address or the username you use to sign into iCloud. To find this, go iCloud Mail > Preferences > Accounts and look for the address labelled "iCloud IMAP". The address should have the ending @icloud.com. So for example, if your iCloud IMAP email address is example@icloud.com, the username you would enter here is "example".

Outgoing server:

Hostname: smtp.mail.me.com

Port: 587

Connection security: STARTTLS

Authentication method: Normal password

Username: same as above

• Not all folders are shown by default. To enable them, right click on your email account in the Thunderbird sidebar, then click Subscribe. Check the boxes for all the folders.
• Local folders are not linked to the correct IMAP folders by default. To fix this, right click on your email account, then click Settings.
  • Navigate to Server Settings. Select the correct folder under "When I delete a message". You can also change it to the Archive folder if you want to archive messages when pressing the delete key.
  • Navigate to Copies & Folders. Select the correct folders for Sent Messages, Archives, and Drafts. For each setting, click "Other", then find the correct folder in the list.
• Install the following Thunderbird addons to make Calendar and Contacts sync. You'll need to do a little config to set these up.
  • TbSync: https://addons.thunderbird.net/en-us/thunderbird/addon/tbsync/
  • Provider for CalDAV & CardDAV: https://addons.thunderbird.net/en-us/thunderbird/addon/dav-4-tbsync/

Hopefully this is helpful to someone in the future.