SEPM mail not working after migrating to new server

I migrated the SEPM from old the server to a new server.

I kept all settings and imported the database from the old server.

I didn't modify the email settings. Our smtp server needs no authentification.

On the new server, SEPM is not sending any mail with the exact same mail settings.

If I try to send a test mail from the mail server setting via SEPM console, following error appears:

If we try to send a mail from the server via telnet, it's working fine without smtp authentification.

I already tried to repair the installation via SEPM setup. (suggestion from https://www-secure.symantec.com/connect/forums/sepm-console-not-sending-auto-email-notification)

SEPM version 12.1.4

Operating system Windows 7