After pestering Microsoft, they finally decided to take a look at our case. I received this email.

Quote
Hello,

Thank you for contacting the Outlook.com Deliverability Support Team.

We will be looking into this issue along with the Escalations Team for the IP address [ 108.174.193.28]. We understand the urgency of this issue and will provide an update as soon as this is available.


Thanks again,

Prem

Outlook.com Deliverability Support

Privacy Statement.

Microsoft Corporation
One Microsoft Way
Redmond, WA 98052 USA

Followed by this one.

Quote
Hello,

Thank you for contacting the Outlook.com Deliverability Support Team.

We have implemented mitigation for your IP (108.174.193.28) and this process may take 24 - 48 hours to replicate completely throughout our system.


Thanks again,

Punithkumar

Outlook.com Deliverability Support

Privacy Statement.

Microsoft Corporation
One Microsoft Way
Redmond, WA 98052 USA

The second email was timestamped at 6:28 AM, so I would assume this problem should clear by Tuesday. Why it takes computers 24 to 48 hours to propagate an implemented change is a question I can't answer, except to say - it is Microsoft.

Paul Schmehl CI 6
geek@stovebolt.com
Stovebolt Staff: Geek