Hi @hughCulling, welcome to the Auth0 Community. Thanks for reading our guide!
The error you’re getting is not related to having a free-tier account. You should be able to follow this guide with the free tier.
This error is generic and happens when there is a problem with the browser cookies or session.
Solution:
Try logging out and logging in again. Then, retry editing and saving your Auth0 application URIs settings.
Alternatively, start from an incognito window or use a different browser and then retry saving your application URIs settings.
We have a topic in the Community about this error. You can check out this link for more details if needed: "Error! You don't have permissions to access the resource" with custom Action.
Hope this helps! Don’t hesitate to reach out if you have any issues or further questions!
Thanks!