Hi Pawan,

Caused by: com.datastax.oss.driver.api.core.servererrors.UnauthorizedException: Unauthorized. User graph_user has no CREATE permission on <all keyspaces> or any of its parents
CREATE KEYSPACE IF NOT EXISTS graphDataTable WITH replication={'replication_factor':1,'class':'SimpleStrategy'}

This part of your stacktrace suggests that something changed on your Cassandra cluster or with the graph_user. So, check the CREATE permission, with your admin or try to create a keyspace with nodetool.

Also note that a few changes in cql properties had to be made (but probably not related):
https://docs.janusgraph.org/v0.6/changelog/

Best wishes,     Marc