During the startup of the broker, the operator tries to check the broker status via the following URL:

http://admin:***@ex-aao-ss-0.ex-aao-hdls-svc.amq-broker.svc.cluster.local:8161/console/jolokia/read/org.apache.activemq.artemis:broker=%22amq-broker%22/Status

Which gives the error message:

context deadline exceeded (Client.Timeout exceeded while awaiting headers)

It seems like the operator is using the wrong URL:
$(service name).$(headless service name).$(namespace).svc.cluster.local

Instead, the operator should use the URL:
$(headless service name).$(namespace).svc.cluster.local