Hi bpike!
I understand that you need to connect your Outlook 365 Webmail to QuickBooks Desktop for Mac. Since the steps shared by my peers give you the same result, it's best to reach out to our Support Team. They can investigate and see what's causing the error.
- Click Help at the top menu and select QuickBooks Desktop Help.
- Tap Contact us and then enter the error message in the question field.
- Select Continue and choose a way to connect with them.
Another way to contact them is by clicking this link: Contact Us.
Keep on posting here if you have more concerns. Take care!
