@Indrek Mäestu
ROOT CAUSE
I hope hadoop.proxyuser.HTTP.hosts was not set to the host where webhcat was running.
RESOLUTION
1. Identify and note the node where WebHCat Server runs
2. Using Ambari HDFS-Configs, check if hadoop.proxyuser.HTTP.hosts is defined in core-site section or change as below
hadoop.proxyuser.HTTP.hosts=*
hadoop.proxyuser.HTTP.groups=*
3. If exists, update the parameter to include the WebHCat node name
4. If not, add the parameter and include WebHCat node name to the same
5. Restart all the services that needs restart including Hive
6. Run Hive service check again
Hope this helps you.