my mail server currently got a problem with sending emails to hotmail.com accounts. My server ip was flagged in spamhaus.org database for not sending a correct header. I think this lead to this problem. But my ip was removed like 1 month ago and I still receive messages that my mail can't be sent.

Error code is 550 SC-001 Unfortunately, messages from xx.xx.xxx.xx weren't sent. Please contact your Internet service provider since part of their network is on our block list. You can also refer your provider to http://mail.live.com/mail/troubleshooting.aspx#errors.

Is there something I can do to resolve this problem?

Sorry for double posting this (in an old discussion and my own one, didn't see how to create a new discussion)

Best regards

Florian Weber