Dear Josh,
Good day!
Thank you for posting to the Microsoft Community. We are glad to assist.
Based on your post regarding "Outlook Dynamics 365 add-in not loading". Please try the below troubleshoot with the Dynamics 365 add-in in Outlook:
Troubleshoot and FAQs about Dynamics 365 App for Outlook.
If the issue still present, you may also (use admin account to) go to Office 365 Admin Center-> Support-> New Service Request. The support engineers there have the correct escalation channel, and this is the most efficient way to report such issue. You can refer to this article to check the way how to raise a ticket: Ways to contact support for business products - Admin help. The engineers in related team have higher permission and resources than us to help check the root cause from background directly.
Note: If you are end user, you may need to contact Office 365 global admin department in your organization to do some standard and particular procedure. For your reference: How do I find my Microsoft 365 admin? - Microsoft Support.
If you still need further help, then please kindly share with me the above feedback after you tried it, and I will do my best to do more research and testing to help you further, thank you.
Thank you in advance for your understanding. Your patience and cooperation will be greatly appreciated. I hope for all the best!
Sincerely,
Microsoft Community Moderator