Template:SMTPnotice
From ULYSSIS documentation
To use a forwarder as an alias, access to the KU Leuven SMTP server is required
Since 24 February 2023, not all students have access to smtps.kuleuven.be by default anymore. If you are unable to send emails after following the instructions outlined in our documentation, then you may have to register on https://ulyssis.org/smtp/ to (re)gain SMTP access.