SMTP Send Problems with Apple Mail
If you are having problems with Apple Mail SMTP using IMAP, ensure you are using the following settings:
Mail > Preferences > SMTP > Edit SMTP Server List > Advanced
Automatically detect and maintain account settings: No
Port: 587
Use SSL: No
Authentication: MD5 Challenge-Response
Allow insecure authentication: Yes
For more information: How to setup Apple Mail
Apple Mail Cannot Send Emails written by UKC average rating 5/5 - 3 user ratings