Hi Brad,
I would like to confirm some information before we start processing the issue:
1. Which plan of Office 365 have you subscribed? Small Business, Midsize Business or Enterprise?
2. Are you using Office 365 pre-upgrade or after-upgrade?
3. Are you using Outlook 2011 for Mac to connect to Office 365?
4. Did you get any error messages? Posting the screenshot of that would be appreciated.
5. Do other users in the same network environment have the issue?
To connect Outlook 2011 for Mac to Office 365, please refer to Set up Outlook for Mac 2011 to work with Office 365.
Please try changing to another network environment to narrow down whether this is a network issue.
If the issue persists, I suggest you check the autodiscover via https://testconnectivity.microsoft.com. Please click Office 365 Tab and select Outlook Anywhere (RPC over HTTP) to start a test.
Best Regards,
Bruce Zhou