Hi @Kitty Clarkson I'm glad that you were able to resolve your issue and thank you for posting your solution so that others experiencing the same thing can easily reference this! Since the Microsoft Q&A community has a policy that "The question author cannot accept their own answer. They can only accept answers by others ", I'll repost your solution in case you'd like to accept the answer .
Error Message:
Running "az iot hub device-identity create" command results in a Unathorized error message with an error code 401002
Solution:
Delete the resource group and hub I had originally created and adding new resources helped resolve this issue.
If I missed anything please let me know and I'd be happy to add it to my answer, or feel free to comment below with any additional information.
I hope this helps!
If you have any other questions, please let me know. Thank you again for your time and patience throughout this issue.