After configuring port 587, as it is described in the article , the following error appears while sending a test message in Outlook:
Send test e-mail message: None of the authentication methods supported by this client are supported by your server.
The error occurs if encryption type is not specified in mail client.
Change the encryption type from
Open Outlook and click Tools .
In the Tools menu, select Account Settings .
Select your email account from the list and click Change . Email settings should be displayed.
Click More Settings... button.
Select Ougoing Server tab > enable My outgoing server(SMTP) requires authentication and Use same settings as my incoming mail server settings.
Set Outgoing (SMTP) to use port 587 and set "Use the following type of encrypted connection = Auto .
Click OK to update the settings.
Click Next and then, click Finish .
If the issue still persists, comment "smtpd_sasl_security_options" parameter in
/etc/postfix/main.cf and restart postfix.