See video showing the issue rhsso-kieserver-error.mp4.
The workbench is not able to connect to the kie-server instance. It throws an error in the log:
Caused by: org.kie.server.api.exception.KieServicesHttpException: Unexpected HTTP response code when requesting URI
Error code: 403, message: <html><head><title>Error</title></head><body>Forbidden</body></html>
I tried both basic and token authentication and both fail.
The requests sent to kie-server from command-line are working though:
<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
<response type="SUCCESS" msg="Kie Server info">
That means the request is being successfully authenticated in keycloack.
This can be reproduced with the lastest RH SSO 7.2 (Keycloack 3.4.3) and the latest workbench version from 7.7.x branch (ER2 build).