Send mail via smtp 25 in mail app to local sever with no username password

cant figure it out how to setup the mail app for this
because it requiers username and password.

try use the email as username and then no password at all.

The SMTP server itself needs to be configured to accept mails without authentication. The Nextcloud mail app cannot bypass security-rules of the mailserver.

Please also notify (keyword: “open-relay”):