The microprofile-conference app integrates multiple services into the application, but this requires CORS header support. When the app attempts to access the health check URL, this is failing with:
00:14:37.877 health:1 Failed to load http://localhost:5050/health: No 'Access-Control-Allow-Origin' header is present on the requested resource. Origin 'http://localhost:8080' is therefore not allowed access.
Previously in the 2017.10.0-MP_12-RC6 fork, there was an org.wildfly.swarm.monitor.deployment.HealthResponseFilter that added the CORS header. I don't see any such support in the current master branch.
The metrics fraction add this via its org.wildfly.swarm.microprofile.metrics.runtime.MetricsHttpHandler#provideCorsHeaders method.