Exception when calling 'continuumXmlRpcClient.getReleaseResultsForProjectGroup(projectGroupId)'

Exception is not visible when trying to retrieve release results for a project group.
You need to perform release and then try to get release results using xmlrpc 'continuumXmlRpcClient.getReleaseResultsForProjectGroup(projectGroupId)'
*************************************************************************

HTTP ERROR 500

Caused by: org.apache.xmlrpc.XmlRpcException: Failed to invoke method getReleaseResultsForProjectGroup in class org.apache.maven.continuum.xmlrpc.server.ContinuumServiceImpl: java.lang.reflect.InvocationTargetException
at org.apache.xmlrpc.client.XmlRpcStreamTransport.readResponse(XmlRpcStreamTransport.java:186)
at org.apache.xmlrpc.client.XmlRpcStreamTransport.sendRequest(XmlRpcStreamTransport.java:145)
at org.apache.xmlrpc.client.XmlRpcHttpTransport.sendRequest(XmlRpcHttpTransport.java:94)
at org.apache.xmlrpc.client.XmlRpcSunHttpTransport.sendRequest(XmlRpcSunHttpTransport.java:44)
at org.apache.xmlrpc.client.XmlRpcClientWorker.execute(XmlRpcClientWorker.java:53)
at org.apache.xmlrpc.client.XmlRpcClient.execute(XmlRpcClient.java:166)
at org.apache.xmlrpc.client.XmlRpcClient.execute(XmlRpcClient.java:136)
at org.apache.xmlrpc.client.XmlRpcClient.execute(XmlRpcClient.java:125)
at org.apache.xmlrpc.client.util.ClientFactory$1.invoke(ClientFactory.java:132)
at $Proxy47.getReleaseResultsForProjectGroup(Unknown Source)
at org.apache.maven.continuum.xmlrpc.client.ContinuumXmlRpcClient.getReleaseResultsForProjectGroup(ContinuumXmlRpcClient.java:564)