Unable to add service pool for HDP in SAM

[gprashmi]

While following the tutorial in this link: https://www.cloudera.com/tutorials/realtime-event-processing-in-nifi-sam-schema-registry-and-superset.html

I am unable to add service pool for HDP in SAM using admin credentials. I am gettingthe below error:

javax.ws.rs.ProcessingException: java.net.UnknownHostException: sandbox-hdp.hortonworks.com

Any help on how to resolve this will be apreciated!