How to configure the 'Domain Name' in the adaptive job server to work in BO 4.2?

I need to complete the following section of the job server setup in BusinessObjects (my assumptions filled in):

Host: send.exampledomain.net

Port: 587

Authentication: Login (has options for None/Plain/Login – so Login selected)

Username: myusername@exampledomain.net

Password: mypassword

I am not sure what to put in the Domain selection.

I’ve tried various ideas in the domain section including 'exampledomain.net' and blank but I just get this error:

login error. [Authentication failed with [Login] authentication protocol. Return code: [SMTP 530 - Authentication required.].]: [CrystalEnterprise.Smtp]