When your Apple ID is protected with two-step verification, you'll need to use an app-specific password to sign in to your email account.

Step 1: Turn On Two Factor Authentication

1. Navigate to the Apple menu > System Preferences > iCloud.
2. Sign in if necessary, then click Account Details.
3. Click Security.
4. Click Turn On Two-Factor Authentication.

Step 2: Generate an App-Specific Password for Postbox

1. Sign in to your Apple ID account page.
2. Under the App-Specific Passwords section, click Generate Password.
   
   
   
   
3. Enter a label, such as "Postbox".
4. Copy the password that is provided. You'll need it later!

Step 3: Use the New Password within Postbox

1. In Postbox, go to Preferences > Security > Passwords > Saved Passwords.
2. Select the incoming and outgoing servers for your iCloud account, then click the Remove button.
3. Restart Postbox.
4. Enter your new Apple App-Specific Passwords when prompted, for both incoming and outgoing servers
   NOTE: You'll need to send a message from the account to trigger the password prompt for the outgoing server.

For more information, please see Using App-Specific Passwords, or visit Apple Support.

Incoming Settings:

• Account Type: IMAP
• Server Name: imap.mail.me.com
• Port: 993
• User Name: (for example, emilyparker, not emilyparker@icloud.com)
• Connection Security: SSL/TLS (if you see an error message when using SSL/TLS, try using STARTTLS instead)
• Authentication: Password

Outgoing Server Settings:

• Server Name: smtp.mail.me.com
• Port: 587
• Connection Security: SSL/TLS (if you see an error message when using SSL/TLS, try using STARTTLS instead)
• Authentication: Password

If you cannot connect, please be sure to check Apple's System Status.

Notes:

Please note that you cannot set up iCloud aliases as if they are email accounts. You must set up your master iCloud account, then set up aliases within that account.