nicolafarina it's my server. And the SMTP server is configured and called the same.
I asked the server admin and told me that port 25 is unsecure, and we need to use 465, but with 'No Authentication' Option, I can't setup SMTP using that port.
If I select 'Same As Remote Mailbox', I got the error 'Configure Mailbox Authentication'.
If I want to choose 'Basic Authentication (Legacy)', I'm asked for a password of no-reply account, password I don't have.
I don't know how to set the secure port and make it works.