I'm using HDP 2.5 and I'm experiencing the issue HADOOP-12787 even though it was merged in 2.4.2
To reproduce it first validate you can correctly read a file in an encryption zone:
hdfs dfs -cat /user/me/somefile.txt
now try going through webhdfs:
hdfs dfs -cat webhdfs://hadoop1:50070/user/me/somefile.txt
I get:
org.apache.hadoop.security.authentication.client.AuthenticationException: GSSException: No valid credentials provided (Mechanism level: Failed to find any Kerberos tgt)
I noticed this because the FileView preview wasn't working with encrypted files