Nationwide recently changed their well-known endpoint to indicate that client_secret_basic authentication is being replaced with tls_client_auth.
When we try to authenticate using tls_client_auth, we receive the following response with a 400 status code: <html><head><title>Request Rejected</title></head><body>The requested URL was rejected. Please consult with your administrator.
How do we go about updating our registration to be compatible with tls_client_auth? Do we need to redo dynamic registration?