Recently, I was trying to setup Hudu to use SMTP over port 465, but it doesn't seem to support this functionality. Upon referencing documentation, it seems Hudu only supports STARTTLS.
STARTTLS is known to be an attack vector. See here https://nostarttls.secvuln.info/
It would be appreciated if Hudu SMTP supported implicit SMTP over 465 instead of requiring STARTTLS over 587.