Please go to "Add your email account" window and then follow the steps to add a GoDaddy email account using IMAP.
1. Click on the dropdown menu and choose IMAP.
2. Now type in the details of your GoDaddy Account using the reference from picture below.
Airmail automatically configures the correct port settings. If Airmail is unable to configure it automatically, please use the following port settings.
Incoming Port: 993 and SSL Authentication
Outgoing Port: 465 and SSL Authentication
If you would like to use a non-SSL connection, please use the following port settings
Finally, click on add the add the account on Airmail.