I think last year people started to write about issues related with Access Denied.
While it might be an individual issue related with an Account, it could also be a systemic issue related with Content and Access Management.
Anyway, the course I am doing like Building Single-Agent Applications on Databrick
contains html content like "we recommend you reach out to the Databricks Academy Learners group in the Databricks Community. .
Then I am getting greeted with Access Denied.
Accessing the community itself, seems to work.