Hi Matthew,
I would like to confirm the following information with you:
• Have you configured your organization's MX record to point to Office 365?
Moreover, I have sent you private messages to collect the tenant domain for further research. You can check private messages by performing the following steps:
• Go to the Your details section on the right side of the community site.
• Click Private messages.
• Click the subject title of the response to read the message.
• You can reply by using the form in this display.
• Click Submit Reply.
Best regards
Shyamal