Webhdfs - error

I am getting following error while writing output to webhdfs.
"Webhdfs check request failed. (namenode: 1*****:50070, Exception: {"RemoteException":{"exception":"StandbyException","javaClassName":"org.apache.hadoop.ipc.StandbyException","message":"Operation category READ is not supported in state standby"}}) {:level=>:error, :file=>"logstash/outputs/webhdfs_helper.rb", :line=>"40", :method=>"test_client"}"
My output config looks like this:
output {
webhdfs {
path => '/patht to folder /fileName{+yyyy.MM.dd.hh}_%{[@metadata][thread_id]}.json'
single_file_per_thread => true
host => 'hostname'
port => '50070'
standby_host => 'hostname'
standby_port => '50070'
user => 'tomcat'
codec => 'json'
flush_size => 32768
idle_flush_time => 300

If I redirect output to type file and write JSON file it is working..
Anyone using Webhdfs has seen this kid of error?