At this time mail sent from our DE SMTP server and mail forwarded from one of our US MX servers to outlook.com, hotmail.com, and live.com is being blocked by Microsoft. We're working with Microsoft to correct the problem.

In the interim:

• DE SMTP users can work around the SMTP block by configuring their clients to use smtp2.de.opalstack.com as their outgoing mail server.
• US customers who use mail forwarding can work around the MX block by creating new MX records for mx2.us.opalstack.com with priority 5 and mx1.us.opalstack.com with priority 10.