The documentation portal is undergoing maintenance. During this period, you can't create any new user credentials. If you do, you'll need to recreate the user credential after the maintenance period ends.
The Blaze and Spark engines require access to the Hive staging directory. You can use the default directory, or you can create a directory on HDFS. For example, if you create a directory, you might run the following command:
hadoop fs –mkdir /staging
If you use the default directory or create a directory, you must grant execute permission to the Hadoop impersonation user and the mapping impersonation users.