API Explorer presents a '401 Unauthorized Error' whilst testing APIs in conjunction with the OAuth 2.0 Client Credentials grant type.
Per the OAuth 2.0 IETF RFC 'Client Credentials' grant type is only usable with confidential clients.
Edit the published application and change the grant type from public to confidential.
To edit an existing application's grant type:
1. Log in to the CA API Management SaaS Portal
2. On the navigation bar, click Applications.
3. On the Actions menu beside the Application, client Edit.
4. Edit the application grant type:
5. Click Save.
6. Repeat the API Explorer test as outlined in the following the Test and Explore APIs documentation.