i install one dnn with n portals, for enabling the SMTP setting for each portal i do the following steps:

• i create an admin user with email "info@domain.com",
• set the site admin to this user

• change the "SMTP mode" to portal in /Admin/Site-Settings -> advanced setting and set the smtp information in related fields

after click to "Test SMTP Settings" get this error:

"There has been an error trying to send the test email. The error is:
There is a problem with the configuration of your SMTP Server. Mail was not sent."

here is the log message:

"Message:Bad sequence of commands. The server response was: This mail server requires authentication when attempting to send to a non-local e-mail address. Please check your mail client settings or contact your administrator to verify that the domain or address is defined for this server."

"Message:User not local; please try a different path. The server response was: Sender address is not valid for your login. Check your email program settings."

note:

1. the host SMTP setting is work correctly
2. tested dnn versions: 7.4.1 & 7.4.2

any idea please