Ok, we found out yesterday what was wrong with the list: our IP,
together with a whole range from Hetzner, is listed on SORBS as a
dialup/dynamic IP address. Mail servers that rely on SORBS will
therefore not accept mail.

Hetzner has opened a ticket with them last Monday, we have opened a
ticket with them yesterday, but no response yet.

Therefore, I conclude that mail adminstrators would be well adviced
not to rely on SORBS for blocking email - they suck.

If you are hurt by this (hope you can read this through the mailing
list archive ;-)), complain to your mail admin, not to us. Or simply
circumvent the problem by reading the list through Gmane...

Regards,

Cees