Questions with how to add new employee's emails

Thanks for the help in advance. I currently have my own email through Homestead and wanted to add my other business partner his own email. I went to settings > Email Accounts > I clicked new and entered the basic info in. I wasn't sure what type of server to make his email. When I completed his and went to send test email it said can not send since his does not support id "4"   ???    please help