Hi Steve,
Have you tested Exchange Autodiscover using Microsoft Remote Connectivity Analyzer? If yes, please tell me the result.
Meanwhile, please send me the following screenshots by Private Message for further troubleshooting:
1. Host Address.
Login to Office 365 OWA>Click the Help icon (the question mark), and then click "About"
2. Server Settings in Outlook 2007 account settings.
3. Microsoft Exchange Proxy Settings in Outlook 2007 account settings.
I have sent you a Private Message with a subject of "Information Request".
Here are the steps to access the Private Message:
1. Please go to the Your details section on the right side of the community site.
2. Click Private Messages.
3. Click the subject title of the response to read the message.
Thanks,
Edward Qu