Business Central Monitor pod cannot interact with kie-server pod

Issue

Kie Server could connect to controller successfully and custom queries have been registered by controller. However, when access to Execution Servers page on business central, popup with the following message appears.

  Unexpected error
  An unexpected error happened. Please try again in a few moments.

and the following error is shown when clicking "Copy error details" link at bottom right corner.

Error: | Uncaught exception: CDI Event exception: CommandType=CDIEvent, BeanType=org.kie.server.controller.api.model.events.ServerInstanceUpdated, ToSubject=cdi.event:org.kie.server.controller.api.model.events.ServerInstanceUpdated, BeanReference=ServerInstanceUpdated{serverInstance=ServerInstanceKey{serverInstanceId='myapp-kieserver myapp-kieserver-14-dqv2m:80', serverName='myapp-kieserver myapp-kieserver-14-dqv2m:80', serverTemplateId='myapp-kieserver', url="" href="http://myapp-kieserver-14-dqv2m:80/services/rest/server'" target="_blank">http://myapp-kieserver-14-dqv2m:80/services/rest/server'}} sent to [unavailable] Caused by: Parameter named 'value' should be not null! | Uncaught exception: CDI Event exception: CommandType=CDIEvent, BeanType=org.kie.server.controller.api.model.events.ServerInstanceUpdated, ToSubject=cdi.event:org.kie.server.controller.api.model.events.ServerInstanceUpdated, BeanReference=ServerInstanceUpdated{serverInstance=ServerInstanceKey{serverInstanceId='myapp-kieserver myapp-kieserver-14-dqv2m:80', serverName='myapp-kieserver myapp-kieserver-14-dqv2m:80', serverTemplateId='myapp-kieserver', url="" href="http://myapp-kieserver-14-dqv2m:80/services/rest/server'" target="_blank">http://myapp-kieserver-14-dqv2m:80/services/rest/server'}} sent to [unavailable] Caused by: Parameter named 'value' should be not null! | Uncaught exception: CDI Event exception: CommandType=CDIEvent, BeanType=org.kie.server.controller.api.model.events.ServerInstanceUpdated, ToSubject=cdi.event:org.kie.server.controller.api.model.events.ServerInstanceUpdated, BeanReference=ServerInstanceUpdated{serverInstance=ServerInstanceKey{serverInstanceId='myapp-kieserver myapp-kieserver-14-dqv2m:80', serverName='myapp-kieserver myapp-kieserver-14-dqv2m:80', serverTemplateId='myapp-kieserver', url="" href="http://myapp-kieserver-14-dqv2m:80/services/rest/server'" target="_blank">http://myapp-kieserver-14-dqv2m:80/services/rest/server'}} sent to [unavailable] Caused by: Parameter named 'value' should be not null! | Uncaught exception: CDI Event exception: CommandType=CDIEvent, BeanType=org.kie.server.controller.api.model.events.ServerInstanceUpdated, ToSubject=cdi.event:org.kie.server.controller.api.model.events.ServerInstanceUpdated, BeanReference=ServerInstanceUpdated{serverInstance=ServerInstanceKey{serverInstanceId='myapp-kieserver myapp-kieserver-14-dqv2m:80', serverName='myapp-kieserver myapp-kieserver-14-dqv2m:80', serverTemplateId='myapp-kieserver', url="" href="http://myapp-kieserver-14-dqv2m:80/services/rest/server'" target="_blank">http://myapp-kieserver-14-dqv2m:80/services/rest/server'}} sent to [unavailable] Caused by: Parameter named 'value' should be not null!

i.e. host name in url is pod name(i.e. myapp-kieserver-14-dqv2m in above example).

Further more, Manage and Track menu does not work as well.
How does it get to work?